when a Texas Ranger is called to a crime scene how do they collect the clues that help them capture a criminal you'll see how science math and photography can help solve a murder mystery when we're called to a crime scene our objective is to collect and preserve the evidence so that it can be used in court at some point in time we'll take a video camera and we'll videotape the entire scene and what it does is it provides a permanent record for what we see when we walk in and that is used in court to
give the jury an idea of what the crime scene looked like as we approached it and first began our investigation we take still photographs to completely and totally document the crime scene but I always think in my mind if something happens and we don't find whoever did this if in 40 years if an investigator picks up this file and they want to reopen this case will they be able to look at my photograph and be able to step back in time and feel like they're in the room so when I take photographs I take a
lot of photographs I take pictures of items in that room that may be insignificant to me at the time but in 40 years someone else looking back on that that may be very significant after we did the uh videotaping and the photography I use what's called an alternate light source now this alternate light source puts out different waves of light and light is measured in waves and the different wavelengths create different colors and the color that you saw me using today was blue and the goggles that you saw me wearing were yellow and when I
combine these two colors together it filters out certain lengths uh wavelengths of light and allows me to see physical evidence that may be on the body or at the crime scene that I'm not able to see with the naked eye we call this trace evidence so the purpose of gathering physical evidence and particularly trace evidence is to be able to determine who may have been at this crime scene which helps us determine who committed the crime we have the markers that are numbered one through however many we need we place them within a crime scene
to document evidence that is going to be within that crime scene placing the markers helps you to organize your evidence so when you document it on paper you can correspond a number with the item there is a scale on the edge of each marker you place the marker parallel with the item of evidence that assists you whenever you take photographs you can get an accurate measurement of whatever that piece of evidence is we do a scale diagram of each crime scene we would use tape measures and we would run an x- axis and a y
AIS your x- axis is going to be your Baseline your y AIS is going to be how you measure your points off of your x-axis you'll be able to tell distance between items of evidence and pieces of furniture in the room doorways Windows when we do our sketch will know exactly how they fit and where they are in relation to other things that are in the room a fingerprint is always something that we look for and we always look in common areas such as door knobs or locks anywhere where anyone would have touched something to
enter in or exit a room we swab for DNA in areas that we normally look for fingerprints also DNA is your biological iCal fingerprint everyone's is different except for if you have an identical twin then uh that twin will have the same DNA as you you can find DNA in saliva you can find it in blood you can find it uh from skin cells from where anyone touched a surface we swab the area in question and then we put it back into a portion of the envelope and then we secure it and seal it inside
of another envelope once the crime lab gets them they will remove them from the package in a sterile environment and they will test them for DNA and there's a possibility of three people coming up with DNA on one swab from a door knob um but their our crime lab has the technology to be able to separate those dnas uh into separate individuals when the evidence collected is combined with other investigative work such as suspect interrogations and forensic sketches a case can then be taken to trial Integrity is is the thing that shines through when you
go to court the defense often times will try and attack the Integrity of the uh officer who's doing the investigation in order to create Reasonable Doubt and get their client off when you have integrity in everything that you do then it makes it very difficult for them to to make that case we owe it to the victims we owe it to society we ow we owe it to the people of the State of Texas to find the truth and to make sure whoever is responsible for whatever crime is prosecuted and convicted
