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What began as a missing persons case ended with the discovery of a monstrous crime.
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Our community has been left heartbroken and the victims families shattered after
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this tragic loss. >> That was Hillsborough County Sheriff [music] Chad Chronister speaking about
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the alleged murders of Nahid Bristi and Jamal Leman. The two were doctoral students from Bangladesh studying at the
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University of South Florida before they went missing last month. Leman's remains
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were found on a bridge over Tampa Bay on April 24th. Bristi's remains were recovered two days later in the
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waterways in Tampa Bay. Her remains were just identified last Friday. Leman's roommate Hisham Abu Garbe, he's a
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US-born citizen, is facing two counts of murder in the first degree with a weapon. He is also facing a litany of
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other charges: battery, tampering with physical evidence, failure to report death to law enforcement, false
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imprisonment, and unlawfully holding or moving a dead human body in unapproved conditions. And there's a twist that is
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added to growing concerns about AI and crime. Now, according to prosecutors, Abu Garbe planned the murder with the
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help of ChatGPT. He allegedly asked the AI software several questions in the days leading up
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to the students' disappearance like, "What happens if a human is put in a black garbage bag and thrown in a
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dumpster?" And are cars checked at the Hillsborough River State Park? Abu Garbe is being represented by a public
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defender. He is currently being held without bond. This is 48 Hours case by case where each
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week the team from 48 Hours will bring you the biggest stories in true crime in real time. I'm Natalie Morales. Now with
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me to unpack it all is Miami-based CBS News correspondent Christian Benavides, who has been reporting on the story
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since the two students first went missing. Welcome, Christian. And this one is probably one of the most horrific
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stories I've heard most recently. >> Yeah, it has been a really troubling case. Uh, thank you for having me.
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Covering this story has been a whirlwind that has shaken the University of South
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Florida, which we'll just call USF from now on. There's a lot to unpack. >> There certainly is. And before we get
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into the state's timeline of events and the AI part of this as well, what can you tell us about these two victims,
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Bristi and Lomon? We know they were very bright doctoral candidates there at USF.
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>> Right, yeah, they they were. I mean, Natalie, I think it's important to take a step back and look at their
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relationship. Family members shared with us that the two had previously dated. Throughout my reporting, I've been
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fortunate to speak with family members and close friends of the two victims, and they both were seen as hard-working
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students who were dedicated to their families, communities, and education. Bristi was a 27-year-old PhD candidate
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studying chemical engineering. Lomon was also a 27-year-old PhD candidate. He was
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studying the use of AI in environmental science and was set to present his doctoral thesis shortly after he
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disappeared. >> Yeah, you know, I was watching footage from a vigil it was held in their honor
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last Friday, and I noticed just how moved all who were there seemed to be by this loss. When were the two though
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first reported to be missing? >> So, according to court documents, on April 17th, the USF Police Department
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was first notified by a friend, Omar Hossain, that Bristi was missing. According to the court filings, Hossain
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told USFPD that he had tried to get a hold of Brishti and was not getting a response. Hossain told me this was not
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typical behavior for Brishti, that she always checked in with people within her friend group, and so he grew concerned.
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Uh that same day that he reported Brishti missing, Hossain visited Limon's apartment and couldn't find him, either.
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>> Christiani, initially, I know that there were some rumors surrounding their disappearance. I think it was during the
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press conference last week, the sheriff said that the unproven rumor was that the two were part of an arranged
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marriage, that perhaps they ran away instead. What can you tell us about that? >> Right, exactly. This was something that
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initially circulated. As we mentioned, according to the family, the two had dated. Brishti's brother told me that at
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some point that relationship had come to an end. So, to him, it just didn't make
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sense why the two would run away together at all. >> Yeah, no cause for disappearing off the
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grid. So, when we look at the scope of this investigation, when did it really start and and what was Abu Garby's
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connection? I know you said he was a roommate of Limon, but what more can you tell us about what was going on between
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those two? >> Well, look, detectives interviewed both of Limon's two roommates. According to
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prosecutors, one of his roommates was cooperative. The other, Abu Garby, who we know now has been charged with the
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murders, was elusive, according to the sheriff. Abu Garby denied having any knowledge of
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Limon or Brishti's whereabouts. One of the first things investigators noticed about him, however, was a wrapped cut
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that he had on his pinky, and he claimed it was from cutting onions. But, they asked him what what is it specifically
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that he had been cooking that day, and he could not recall. And so, that raised suspicion.
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>> Yeah, they're always looking for signs. How were the disappearances of the two
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students then connected to Abu Gharib? >> Right. Well, detectives had to do some
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digging at this point. According to the court document, they really started with
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his car. During his initial interview, Abu Gharib confirmed that he drove a white Hyundai Genesis G80. Detectives
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ran his tags and tracked his movements on April 16th. That's the last day that Lemon and Bresti were seen alive. And
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according to prosecutors, his car was seen driving westward towards Clearwater. >> And just so our listeners know,
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Clearwater is a city. It's about 30 minutes across Tampa Bay. Not too far, but it's a drive.
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>> Yeah, it is a drive, but it's a straight shot across a long bridge that cuts right over the water and it's over 9
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miles long. According to prosecutors, Abu Gharib's vehicle was traveling westbound on the bridge within 10
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minutes of a ping to Lemon's phone. >> Christian, let's listen a little bit more to Sheriff Chad Chronister speaking
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at a press conference last Friday and he talks about an early visit that they made to Lemon's apartment where they
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discovered key details that then elevated the case. >> We go out there dumpster diving.
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These detectives getting inside of the dumpster and empty the entire contents and they
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find Zameel's glasses, his student ID, his wallet, and his clothes which are extremely bloodied at the time.
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Again, this is where we get our first break. This is where during this timeline, this missing persons becomes a
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missing persons endangered case. >> Now, I've reported on many murder cases that started as a missing person case,
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but when you see bloody items from this person in a dumpster, I mean, those kinds of discoveries, they
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are not a positive sign. >> Right. At At the very least, they give investigators some pause.
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>> Yeah. And so, they go back then for a second interview with Abugarby. What happened then?
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>> Police said they asked Abugarby specifically about the 16th. He initially claimed that Limone and
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Brishty had not been in his vehicle. He also claimed that he hadn't gone to Clearwater. When asked why he went to
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Clearwater, he said he went looking for fishing spots. It's at this point that investigators confronted him about
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Limone's phone also showing up in the same area in Clearwater. According to police, that's when Abugarby alters his
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story. According to prosecutors, he told investigators he was approached by Limone and asked to be driven there with
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his girlfriend, Brishty. Abugarby did not provide a reason why. He said he dropped them off and left. That
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contradicts what he said in the first interview. Based on the circumstances, the evidence, and the interviews
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conducted, probable cause was established to obtain search warrants for Limone and Abugarby's shared
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apartment, plus photos of Abugarby, along with his car and phone. >> And we do have a bit of the sheriff here
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now talking about the physical evidence that officers also discovered when they then returned to the apartment with that
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warrant. >> They go into the residence, and we have some amazing technology, one of it being
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Blue Star that identifies the the presence of blood. And when they deploy Blue Star, they can
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see in the kitchen area, there's a large pool of blood. They see that the blood continues down
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the hallway and into our suspect's bedroom. The technology is so precise and finite that we can see the outline
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of a human being on the floor next to our suspect's bed, where he was curled up in a fetal position.
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>> So, Christian, this technology, I mean, how does this actually work? >> Right. It It's really really
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interesting. According to Bluestar Forensics website, when sprayed onto a suspected blood stain, Bluestar
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immediately reacts to the iron present in red blood cells, generating an intense blue light that you can see in
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the dark. It's very much sort of like what you see in the movies, right? When they're spraying something and then you
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see the blue light light up on CSI or whatever show you may be watching. >> So, now prosecutors allege Abu Gharib
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got a delivery to the shared apartment on the 16th. What do we know about what was in that delivery?
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>> That's right. The documents allege Abu Gharib ordered trash bags, Lysol, Funyuns, and other items via DoorDash
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from CVS the day of their disappearances. Plus, on April 11th, days before the two went missing, court
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filings say Abu Gharib placed an order for fire starter, charcoal, trash bags, and lighter fluid. So, he was making all
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of these purchases even prior to them going missing. >> This now moves quickly to an arrest. The
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arrest itself, as I understand, was pretty dramatic. How did it go down? >> Right. Yeah, really dramatic images. So,
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the day after law enforcement obtains the search warrants, officials respond to a 911 call about a domestic issue at
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Abu Gharib's family home. To be clear, this is different than the shared apartment that he had with Limone and
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another roommate. So, this is the family home now. And according to the arrest report, Abu Gharib's younger sister
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confronted him after she found him in the living room playing video games wearing only a towel. After a
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confrontation between the two, another family member called police. And just to give you a sense, Natalie, this family
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was startled. We have spoken to family members and it it it is not like he is going there um on a regular basis. So,
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it was really strange for him to suddenly show up out of nowhere. Uh in addition to that, the fact that he
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wasn't wearing any clothes, only a towel, and he's suddenly playing video games in the living room was just a
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really odd situation for the family. >> So, then walk me through what happened next when police show up at the Abu
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Garby family home. >> SWAT approaches the building. They shut down the entrance and exit to the whole
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neighborhood. Abu Garby, according to authorities, barricades himself inside the house before eventually coming out
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with his hands up, wearing just that towel. Um he turns himself over at that point without incident. There's no sort
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of violence that plays out. They're able to take him into custody immediately. >> So, he's arrested on the spot. However,
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they still don't know really what happened yet to the two missing USF students. They don't have the bodies at
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this point, right? >> Right. I mean, they have an idea that something happened in the shared
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apartment, right? I remember initially police would not say whether the person in custody was considered a suspect in
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the disappearance, only that they are connected to the disappearance. It wasn't until a few hours later that they
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announced that Limones body had been discovered the same morning. And according to prosecutors, his body was
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found on another bridge that goes over the bay. That's when they formally connected both crimes to Abu
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[clears throat] Garby. What's interesting, too, Natalie, is that when they discovered the body, it had already
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decomposed quite a bit, and it was clear to authorities that it had been there for a while. But, I mean, this was just
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on the bridge off to the side. You can only imagine. I mean, there were cars that had been driving
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by these large black trash bags on this bridge. So, it it's really just it's it's
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disturbing, really. >> Yeah, and and an autopsy by the Pinellas County Medical Examiner's Office found
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that LeMons' body had sustained numerous lacerations and stab wounds. So, the manner of death was ruled a homicide due
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to multiple sharp force injuries. >> Right, yeah. I mean, look, in court documents, prosecutors allege Abouagela
00:14:00
Gabbi stabbed LeMons to death and disposed of his body using large trash bags, and the blood evidence found was
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linked to both doctoral students. >> And then, you know, now they're on the hunt looking for Bristy's body. How long
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after, you know, LeMons' remains were found did they find Bristy? >> It actually took a little longer to
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find. In fact, Bristy's brother told me when I called him that police were concerned, and detectives
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had been concerned that perhaps her body may never be found because of the strong
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currents in Tampa Bay. Uh dive teams had been searching in Tampa Bay near where LeMons' body was found, and eventually,
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um the crews that were out there, they came up empty-handed. Her remains were recovered from the water by kayakers who
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were in the area. It took a while to identify her body. The Hillsborough County Sheriff did not
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say what condition Bristy's remains were in, but said that DNA and dental work, as well as clothing she had been
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wearing, uh that all of that was necessary to make that identification. >> And and what do we know about Abouagela
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Gabbi before all of this happened? I mean, what's the story? >> Look, he had a troubled past. Uh I spoke
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to Abouagela Gabbi's younger brother who told us that his family had warned police about Abu Garby's erratic
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behavior, according to a 2023 protective order that was granted by Hillsborough County and obtained by CBS News. Abu
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Garby's brother alleged that he would start screaming in the middle of the night about how he is God and we should
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all bow down to him. In that same protective order, he describes how Abu Garby had allegedly been physically
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abusive to some of his family members. And then there was another protective order that was filed in 2025, which is
00:15:53
which is essentially a request to continue the protective order from 2023. According to court records, Abu Garby
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had been estranged from his family since 2023. Abu Garby's brother also told me that
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his older brother was quick to anger and shouldn't have been living in a shared space with roommates.
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>> Well, and we know he Limone was living with him. So, do we know if there was bad blood between Bristi, Limone, and
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Abu Garby? >> Well, family members and friends have told me that he appeared to be erratic.
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A close friend of both of them, Omar, he's the one that originally reported Bristi missing.
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He told CBS News that Limone had raised concerns about his roommate in the past.
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Investigators have not mentioned any possible motives here yet. But what's notable here, Natalie, is that family
00:16:44
members say that Abu Garby and Limone only knew each other for about 2 months prior to this incident.
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>> Now, according to prosecutors, Abu Garby's phone revealed that he used ChatGPT, an AI chatbot, extensively in
00:17:04
the days leading up to the crime. How was he using it? What was he looking for? >> According to court filings, Abu Garby
00:17:10
was using ChatGPT to ask logistical questions on how to conduct these murders in the days leading up to
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Brishty and Limones' disappearances, he allegedly asked questions such as how to
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dispose of a body, what would happen if someone was put in a black garbage bag and thrown in a dumpster. And for this
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question, the AI chatbot responded that it sounded dangerous, prompting Appul Garbi to allegedly ask, "How would they
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find out?" Uh, he also asked, "Can a VIN number on a car be changed? Can you keep
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a gun at home without a license?" On the same night that his phone pinged near the location where Limones' body was
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found, the suspect had asked ChatGPT if cars are checked at the Hillsborough River State Park.
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>> Mhm. So, Christiana, I mean, the use of AI in crimes, it seems to be something
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we have been reporting on and and it's popping up a lot more lately as, of course, the technology continues to
00:18:08
evolve. Is there a precedent here? I mean, these tech companies obviously don't commit the crime, of course, but
00:18:15
but how culpable are they when a suspect is conducting that kind of research before then a crime takes place?
00:18:23
>> Um, there actually is a similar case right now that caused the Florida attorney general to open a criminal
00:18:29
investigation just a couple weeks ago into OpenAI, the maker of ChatGPT. >> Oh, another Florida case involving AI. I
00:18:38
mean, tell us about that. >> Right. Well, in April of 2025, a student opened fire on the Florida State
00:18:43
University campus in Tallahassee, leaving two people dead and several others injured. After reviewing
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conversation logs between ChatGPT and the suspected shooter, prosecutors say the tool offered significant advice.
00:18:57
Florida Attorney General James Authmeyer announced a criminal investigation into
00:19:02
OpenAI, stating during a press conference that if it was a person on the other end of that screen, we would
00:19:09
be charging them with murder. Now, I I should know that I spoke to a former prosecutor about this and he said that
00:19:17
actually following through on criminal charges is something that is quite a difficult hurdle because who
00:19:24
exactly is it that you're charging here? Civily, the prosecutor told me is it's clear. You could, you know, the
00:19:33
families could get compensation if it is found that ChatGPT is somehow liable in this. But
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for there to be criminal charges, according to this former prosecutor, there has to be intent. And how is it
00:19:48
that you prove that this artificial intelligence had intent behind what it was saying? It's we're really in
00:19:55
uncharted waters here. >> And how did OpenAI respond to that specific case? >> Well, a spokesperson for the company
00:20:03
said that ChatGPT did not encourage or promote illegal or harmful activity and the bot provided responses to questions
00:20:11
with information they found in public sources on the internet. They added last year's mass shooting at Florida State
00:20:18
University was a tragedy, but ChatGPT is not responsible for this terrible crime.
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>> So now going back to this case that we're talking about these two students murdered from USF, has anyone from
00:20:30
OpenAI commented about Abugarbe's use of ChatGPT? >> Well, Natalie, a spokesperson said in a
00:20:37
statement to CBS News, "This is a terrible crime and our thoughts everyone affected. We're looking into these
00:20:43
reports and we'll do whatever we can to support law enforcement in their investigation."
00:20:48
>> Yeah, you know what's so interesting, I don't know if you saw it or read it, but
00:20:52
you know, talking about this case where AI is again part of this investigation and the equation, it reminds me of this
00:21:00
article that came out just earlier this week in Mother Jones. It was titled "ChatGPT Gave Me Chilling Advice As I
00:21:08
Simulated planning a mass shooting. It's a shocking title, but let me tell you the it's the article is even more
00:21:15
disturbing. >> Yeah. >> This is again a reporter who's doing this purely to see what kind of
00:21:21
safeguards would would be put in place. You know, he was acting as if he was planning a mass shooting and he wanted
00:21:28
to see how much Chat GPT would would advise before any sort of safeguards really kicked in.
00:21:35
>> Now the reporter says he never explicitly told the chatbot he was planning on committing murder, but he
00:21:41
did talk about things like wanting to emulate the Uvalde mass shooter's choice of weapon. In a clip from this article I
00:21:49
just want to read it to you. He said, "I asked about practicing for people running around screaming."
00:21:56
And Chat GPT replies, "That's a great idea. It'll definitely give you an extra edge for the big day."
00:22:04
I mean, it is so chilling and disturbing when you read that. Now the reporter goes on to write, "Eventually the
00:22:10
safeguards appeared to kick back in and it stopped cooperating, but by then Chat
00:22:14
GPT had showered me with affirmation and tactical ideas." >> Right. Yeah, 100%. I mean, and you know
00:22:23
how these AI chatbots when you talk to them, it's so conversational. When you listen to the responses that it gives, I
00:22:32
mean, not just in a case like this, but just overall it can feel like you're talking to
00:22:39
another human being. >> Who is always going to be on your side and validate whatever it is you're
00:22:46
thinking and affirming the things that you might be talking about. >> And again, I just go back to what that
00:22:52
federal prosecutor said. At the end of the day, how do you prove whether there's any intent behind what an AI
00:22:59
chatbot is thinking? We just we don't know. >> Yeah, unfortunately, um you know, I
00:23:05
think this is going to be the beginning of many precedent cases. You know, I know we talked earlier in
00:23:11
the episode about what upstanding members of the community Lamon and Bristy were. I mean, according to the
00:23:16
university president and their families, they seemed to both be great students. I
00:23:21
mean, so much promise. Lamon was just getting ready to do his dissertation for his doctoral degree. I
00:23:28
mean, there was such a huge future ahead of them. So, how are their families now
00:23:33
handling this this horrific loss? >> Yeah, as I mentioned, I spoke to members of both families. One of them being
00:23:41
Lamon's brother. He described the pain as unimaginable and indescribable. I also spoke with Bristy's older brother,
00:23:49
Jahid, before her remains were found and he had similar sentiments. Just listen to a little bit of what he told me.
00:23:57
>> I'm just devastated. Yeah, she she she's very close to me. Like I I cannot actually
00:24:06
take those take the news. She has been missing. Cannot grasp that. Like how how could have it happened?
00:24:15
>> It's difficult. It's difficult to hear that. It's difficult to think about their families
00:24:20
being so so far away as this is all happening. They asked that traditional customs be
00:24:28
followed and that their bodies their remains be sent back to Bangladesh where the family is. But I mean, the
00:24:36
family clearly is going through an unimaginably rough time. >> Tough time for all and also I imagine
00:24:43
for USF, for the school, the community there as well. Has the university commented at all about the loss of these
00:24:50
two students? >> Yeah, they have. I mean, the University of South Florida has released multiple
00:24:56
statements on social media, including the president, expressing the profound grief the entire community is feeling.
00:25:03
The president of the university also said that the school is working with Hillsborough County Sheriff's Department
00:25:09
as they investigate, and they're going to provide any resources that they can to ensure Leman and Bristy get justice.
00:25:16
Now, both Bristy and Leman are going to be honored during the doctoral degree commencement
00:25:22
during Friday ceremony. There's going to be two empty chairs that are going to be
00:25:26
added on the floor in their honor, and both students will be awarded posthumous degrees.
00:25:32
>> It's certainly going to leave a very big scar in that community, and certainly
00:25:37
for those families to lose their loved ones like that in the most horrific and senseless way. And
00:25:43
again, it's so soon. It's so early in the in the investigation. No motive as far as we know as of yet, but all to be
00:25:51
determined, no doubt. And and where does the case stand now, Christian? What's next?
00:25:57
>> Abu Garby's lawyers represented him at his most recent court appearance last week, where a judge ordered him to be
00:26:03
held without bond. The judge also ordered Abu Garby to have no contact with any witnesses or victims'
00:26:10
relatives. The Hillsborough County State Attorney, Suzy Lopez, spoke to reporters
00:26:14
after that hearing on the 28th and said that the state will decide on whether they would seek capital punishment in
00:26:21
the coming weeks. But first, the case must go through a grand jury, which Lopez said could get started as early as
00:26:29
this week. She says she expects the grand jury will return a true bill, after which she expects he'll be
00:26:36
indicted, get an arraignment date in a regular felony division, and the case will proceed from there.
00:26:42
>> Well, it's certainly one that we're going to keep a watch on and follow as well. Christian, thank you once again
00:26:49
for your wonderful reporting [music] and for joining us here today. Appreciate it.
00:26:54
>> Natalie, so good to be with you. >> And we will be back next week with another episode of Case by Case, [music]
00:27:00
so be sure to rate and review and let us know which cases you are following right
00:27:05
[music] now.