But crime scene investigations in the real world are rarely so simple. Detective Joanna Grivetti leads the crime scene investigation unit for the police department in Richmond, California, one of the most dangerous cities in America.
Share37 Shares Forensic movies and TV shows are awesome, but they are often so very wrong about so many things. As a crime scene investigator myself, I hope this list clears things up for everyone.
While they are quick, these instruments can only process five samples at a time. So in a hour period, the department can run the machine 16 times, meaning that even if someone is constantly at the machine, only 80 samples can be analyzed each day.
He first has to wait in line for a few days.
But there is again a problem. The bigger machines have bigger plates that can run hundreds of samples at a time, but they can only be used once. Also, these larger machines are not RapidDNA systems, so it usually takes about three days for the samples to go through all the required steps even without backlog.
So again, we have DNA samples to run and use three plates with slots. Two of those plates are full, and one of them is only half full. So the investigation is going to have to wait until more crime is committed and more samples are collected to fill up that plate.
No matter which system is used, DNA testing is going to take at least a few days. This leads to no visible print on the gun. Have you ever had your fingerprints taken? What if they touch the barrel? The barrel is the best hope for finding fingerprints.
If fingerprints are to be found, that is generally where they are. They will first remove the magazine and empty the chamber. How do they do this? By handling the gun and touching it all over. Are they wearing gloves? Can delicate fingerprints survive being assaulted by gloved hands?
Chetvorno Contrary to popular belief, blood does not glow under ultraviolet UV light. UV lights are used all the time on network television to create that classic blue glow.
Many bodily fluids do glow under UV light—semen, urine, breast milk, saliva—but blood, rather than glowing, turns super black.
You can make blood glow, just not with a UV light! In order to visualize the reaction of luminol with blood, it needs to be pretty dark. Also, the fluorescence only lasts a few seconds. The investigators need to guess where the blood will be, set up their cameras, spray the luminol, and then quickly take a picture before the glow disappears.
There are two suspects—his wife and his close friend. A wife hugs her husband, holds his hand, scratches his back, shares the same bathroom, and so on. This type of scenario happens more than you would think, and DNA is usually pretty useless in these cases. A man robs a store. He is seen on surveillance at one point opening a refrigerator door to grab a drink.
Is his DNA on the refrigerator door handle? Is the DNA of every other person who opened that same door to buy a drink also on the door handle?
It will actually take less time for the analyst to process because there are fewer lines there to analyze. The analyst looks for as many identifying features on the print he or she is given as possible and then looks for a fingerprint with the exact same identifying features in the exact same positions.
If it were a tiny partial print with very few features, no matter how closely the analyst looked at that thing, there would be only so many features distinct enough to count as identifying features.
The print would have to be thrown out. If the fingerprints match, the case is even stronger. Most other analyses are not like this, though.
Fibers are even less specific. These analyses will help a case, but they absolutely cannot prove beyond a doubt that a suspect was the killer. Give me more evidence!DNA (Forensic Biology) Learn Genetics. Extract human DNA and run it on a gel in the University of Utah's virtual laboratory.
This site has information on genetic cloning and biotechnology as well. CODIS. The FBI's Combined DNA Index System (CODIS) explained. Forensic DNA. Everything about forensic DNA collection and analysis.
DNA (Forensic Biology) Learn Genetics. Extract human DNA and run it on a gel in the University of Utah's virtual laboratory. This site has information on genetic cloning and biotechnology as well. CODIS. The FBI's Combined DNA Index System (CODIS) explained. Forensic DNA. Everything about forensic DNA collection and analysis.
In rape cases, CSI viewers were less likely to convict if DNA evidence was not presented.
In both the breaking-and-entering and theft scenarios, CSI viewers were more likely to convict if there was victim or other testimony, but no fingerprint evidence.
CSI Basics Crime scene investigation is the meeting point of science, logic and law. "Processing a crime scene" is a long, tedious process that involves purposeful documentation of the conditions at the scene and the collection of any physical evidence that could possibly illuminate what happened and .
Alec Jeffreys pioneered the use of DNA profiling in forensic science in (founded in ), then known as the Forensic Science Society, publisher of Science & Justice Real-life crime scene investigators and forensic scientists warn that popular television shows do not give a realistic picture of the work and often wildlly.
Transcript for the FRONTLINE film The Real CSI. DNA is the principal example of real science at work. DNA really is the only discipline among the forensic disciplines that consistently.