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As a crime scene investigator, you can never go into a crime scene with a theory or an assumption. I've spent two
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decades of law enforcement as a crime scene investigator, and I've been sharing my expertise with Ashley Flowers
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on Crime Junkie for years. I'm going to walk you through how we approach a crime
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scene, just like how we train new investigators. As crime scene investigators, we go through a rigorous
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process and use all tools available to answer the questions and solve the crime.
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There are several key steps in analyzing a crime scene. Securing a crime scene is all about
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making sure that evidence isn't tampered with. You don't want any artifact evidence there from somebody coming into
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the crime scene. Meaning, if you have an individual who comes in and leaves their
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DNA, that becomes artifact. It's not evidence to that actual crime. After securing the crime scene, it's a waiting
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game. It's waiting on getting that search warrant. Once you finally get that search warrant, the very first
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thing in that interior barrier is you create a crime scene entry log. Those very first people who go into there are
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your forensic services unit members who are going to photograph and document the
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crime scene. Documentation is the most important thing. This starts on the exterior. Photographs
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are taken of the complete exterior of the house from all sides, all corners of the house. And then you start at the
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entryway of coming into the crime scene, and you photograph everything. You photograph every room from wide angles,
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from every corner. Especially now in the digital age, hundreds if not thousands of pictures. I've seen cases where
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there's upwards of 3,000 pictures. For some of the advanced documentation of crime scenes, you can use 3D
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scanners. You can actually do a 3D fly-through through your crime scene. In crime scenes where we feel there's been
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crime scene cleanup, we can use Luminol. This is Luminol. Luminol is used to identify blood that's
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been cleaned up before. With this product here, you add water to it, you mix it up, and then you spray it on the
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area where you think that blood had been or or any kind of biological fluid, seminal fluid, things like that. And
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when you put a black light over top of it, it'll show you where that area is. Now, we want to start identifying
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evidence. So, here, as we're standing in this room, our biggest piece of evidence here is
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our victim. So, we then take markers, and we put markers down. When we write our report, the victim's body is at tent
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number one. And then we're going to take photographs of our victim with a mark. Bullet holes are going to get number
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two. They're photographed prior to the tent going down, and they're photographed after the tent goes down.
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We always put a scale in that photograph next to that piece of evidence for reference. Continuing through, you would
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mark the blood, photograph beforehand, photograph afterwards. You put a tent. Same thing with the other blood stains,
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and then you work your way out of this room. And here, directly in the hallway, we have bullet casings. Photograph the
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bullet casings, and mark the bullet casings with a tent. So, that's documentation.
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We then get into the collection process, which is super important how you collect
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your evidence and how you package your evidence. So, for example, in this crime scene, if we had a weapon here, we use
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weapon boxes. They have knife boxes, they have gun boxes, they have rifle boxes to be sent to the lab for DNA
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testing. When we collect other evidence, when we start talking about blood, if it's blood on the floor as we have here,
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they swab the blood. And it's really just an extra-long Q-tip, but they're sterile. You let that dry, and then you
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package that either in a box, something a little bit bigger than this, or you package that in a paper bag. We utilize
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paper bags more than plastic bags now because paper bags don't cause mold, don't cause degradation of your evidence
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when you package it. And also, we want to figure out what the trajectory of those bullets were, where they
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originated from and where they ended up. To do that, we use lasers to identify that trajectory of the rounds. So, if
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you know the point where it ends and you know the point in the middle where it kind of comes through the victim's body,
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then you can then create a trajectory where you can go back and create the starting point.
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Then also here, we have broken glass in our dining room area. Again, collect it and placed in a paper bag. And this is
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also key for us because this is a great spot to fingerprint. This is a basic fingerprint kit that's used at crime
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scenes. These kits consist of powder, which is usually graphite, to put on the area where a fingerprint is, the brush
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that you use to dispense the graphite, and then lifting material to actually lift the fingerprint off. At crime
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scenes, we utilize all different kinds of instruments to collect evidence, scalpels, box cutters to be able to cut
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carpet out. We use saws alls to be able to extract bullets from walls. Outdoor crime scenes have their own
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challenges. We're fighting with rain, we're fighting with snow, we're fighting with sun. These footprints that we have
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here become relevant to the crime. That evidence is critical to be processed first. They're photographed and they're
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cast. Same thing with tire tracks. These tire tracks are in a really odd location. Are they connected to the
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crime scene itself? We would still photograph them, we would still take a casting of them.
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When casting tire impressions, footprints, you use something of this nature. This is a shaking cast
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all-inclusive kit that has water already in with the powder. So, what you would do is you'd lay it flat, you'd press on
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the water container, and it would break open, and then you need to get this to like a clay-like consistency, and then
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you pour this into your foot impression or your tire impression. You give it 30 minutes to dry, and then you just pull
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it right up, and you have your impression. We have evidence of disturbed earth here. Did the offender leave and dig
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something and bury the murder weapon here? Did they dig and put other evidence here at the scene? So, they
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have metal detectors that we've used before. They have ground-penetrating radar, where they actually can run over
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that section of earth and identify an anomaly. But, the critical piece of it is is how far down we believe it to be.
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We've used excavation equipment before to recover bodies that have been buried, and we can identify the depth of the
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body. So, what you'll do is dig down maybe a foot above that body, and then from there down you're digging by hand.
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But, any kind of earth that we dig up, we sift everything, and it's sifted for other evidence that may be buried there
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also that we can't physically see. So, some of those other things that we deal with outside, especially outside crime
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scenes where you have a deceased person, a lot of times they're in a state of decomposition, where they're either A,
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maggots have already started to form, or B, you have blowflies flying around the
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body. So, what you want to do is you want to collect those insects, cuz you can send them to an entomologist, and
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they can give you a rough time of death. With a maggot, you can tell how old they
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are and how long they've been there by the size of the maggot. So, that's what an entomologist does. I love maggots.
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Maggots are the best. I'm telling you right now. And then after that, there's always a
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final walk-through. When we start analyzing crime scenes, we try to start a point of entry. Where's that point of
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entry that we think the offender came into the house at? And where is that interaction between both the offender
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and our victim? Point of entry we have here into the house, we saw the broken glass. This is that exterior door. So,
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when the offender broke into the house, he broke the glass and it fell inside the house. And then you kind of look at
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this blood here. Is this our victim's blood or is this our offender's blood that got onto the offender when the
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offender comes out of the room? Or is this somehow an altercation between our victim and our offender and our offender
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is bleeding himself? So, these blood droplets outside of the main crime scene become super important. Because
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obviously as you see here, it does not look like our victim moved after he was shot. Our offender comes into the room,
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he surprises the victim, the victim stands up, is more than likely initially shot here where we have our first set of
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blood stains, and then falls to final rest, and we have the other blood here at final rest.
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So, it kind of gives you an idea of what happened here. But, some of the things that we don't see and are super
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important is the motive. Is anything stolen? Is anything missing? Do we think this person came here to steal something
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or is this personal? These are those key things you start picking up on at crime
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scenes. Taking in all the evidence including statements, what we get at the autopsy,
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helps us create a hypothesis of what had happened at that crime scene. Technology is changing all the time and
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people are really focused on going back to cases, but dusting them off and looking at the evidence and say, "Hey,
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is there something we can do now in 2026 that we weren't able to do 40 years ago.
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Maybe there's nothing we can do today. Maybe there's nothing we can do in 5 years, but we need to preserve that. So,
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if in 10 years from now, if new technology comes about, in case it's not solved, that we can have that for
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future.