Forensic Scientist

Forensic Scientist

LIsa Black

Cape Coral, FL

Female, 49

I spent the five happiest years of my life in a morgue. As a forensic scientist in the Cleveland coroner’s office I analyzed gunshot residue on hands and clothing, hairs, fibers, paint, glass, DNA, blood and many other forms of trace evidence, as well as crime scenes. Now I'm a certified latent print examiner and CSI for a police department in Florida. I also write a series of forensic suspense novels, turning the day job into fiction. My books have been translated into six languages.

SubscribeGet emails when new questions are answered. Ask Me Anything!Show Bio +

Share:

Ask me anything!

Submit Your Question

824 Questions

Share:

Last Answer on September 21, 2020

Best Rated

Is the thing you see in movies where thieves wear "synthetic" fingerprints so that they leave SOMEONE ELSE'S prints behind actually possible in real life? Can you tell the difference between human and synthetic prints?

Asked by DallasR over 7 years ago

This is certainly possible, but would be a very iffy way to frame someone. First you have to talk this other person into cooperating while you make a mold of their finger. THen you can use some epoxy based putty to cast the finger. Provided this goes well the pattern should be an exact duplicate, so that's good. Now you have to coat that with something to form a fingerprint. Don't use your own sweat and oils in case we do touch DNA on the print. On CSI they used cooking oil spray, which might work but depending on how long or short it is until the print is processed, it might be too soft and just smear when the tech powders it. Then you have to put this cast finger to a piece or pieces of evidence that you are SURE the crime scene tech will print. This is where it gets tricky. Say you stage a break-in and you put it on the window frame or broken glass. Maybe the frame is too rough to hold a decent print, maybe the tech fingerprints 15 pieces of broken glass and then gives up. Maybe you take great pains to put it on the murder weapon and then a traumatized witness or a clumsy tech smudges the print when they pick it up. Maybe you leave it on a note in the victim's pocket (paper is also very iffy!) and then EMS cuts the shirt off and leaves it in the driveway or throws it out in the ER or it gets soaked in blood. THEN when the tech lifts the print, it needs to look consistent with the 'background' from the item and the manner in which it was gripped. Of course if the rubber flakes off into the print that might get more attention than you want. THEN if we decide to do DNA analysis on the print (which is possible even after it's been processed with powder or superglue) the DNA results might be utterly negative or show animal strains (?) or whatever. Again, that might raise a red flag with an analyst, or they might simply figure that there wasn't enough sample to get a profile. So you MIGHT get away with it. Or you might not.

Why does DNA testing take so long? Even in high-profile cases, you hear that they're doing DNA tests, but that the results won't be known for days. What part of the process is the bottle-neck?

Asked by sonjalevesque over 7 years ago

I actually haven't done DNA analysis in a lot of years, and that was before STRs (the method mostly used now) but from what I pick up from the analysts, yes, it's not like TV where you wait in the hall for your DNA results. It's a time consuming process and at certain points there's no way to do it quickly. First they have to determine if DNA is present. Then they have to estimate about how much is present, to know if they need to 'amplify' the same or not or how much. Then the actual testing is done. During all this they also need to run positive and negative controls and do other quality control measures. There's also paperwork, lunch breaks and I doubt too many labs operate round the clock. Then of course there's first-in, first-out; your case doesn't get to jump the line, so how long it takes depends on how long that line is. At our state lab it used to be close to a year, but things have gotten much better and now it's more like weeks to months. If we want something more quickly, we can send it to a private lab which can promise us a one-week turnaround--for $1800 PER sample. But even disregarding queues and monetary considerations, even if the lab dropped everything else and worked overtime, it would still take a couple days.  

Oh, and in that vein: what IS the most creative way you've ever seen a criminal try to throw investigators off his scent??

Asked by DallasR over 7 years ago

We had a person borrow money from a kind elderly gentleman, then ask for more and beat him to death when he refused. The person then went home and mailed the victim a check, trying to show that the debt was being paid and there was no ill will. That's what passes for extreme cleverness in my neck of the woods.

How soon after a person dies do you have to remove their organs so that they can still be transplanted to someone else? And does doing an autopsy damage any organs so as to make them no longer transplantable?

Asked by exconill over 7 years ago

I actually do not know that, sorry. I attend autopsies but only to observe, so I don't have anything to do with that--but I can tell you that the organs (except eyes or bones) are all dissected and examined so they would definitely be no longer transplantable. So organ harvesting is done before the autopsy. 

What degree and certification would I need become a forensic scientist? I'm currently majoring in criminology, but would switch if something else was better.

Asked by Alejada over 7 years ago

Again, titles and job requirements aren't uniform, so the only way to know is to call the crime labs in your area or whereever you might be interested in working and ask them. At the coroner's office we had to have at least a bachelor's in a natural science (this was before they had forensic science majors). At the police department where I am now, they only require a high school diploma but you get more points in the interviewing process for having a four year degree, so we all have one. You can also go on the websites for professional organizations such as the American Academy of Forensic Sciences and check out their job vacancy postings and see what the various positions require. Good luck.

And something else I always wondered. Just HOW MUCH of a fingerprint is unique to every human? If someone leaves only a partial print, e.g. a 1/4 of a thumbprint, is THAT unique to him and only him?

Asked by Sascha over 7 years ago

Every part of a fingerprint is unique to the person. Whether the latent print has sufficient information to identify it to a person depends on its clarity and volume and the experience of the examiner. There's usually more activity around the center of the finger pad than at the edges or the tip, for example. But exactly how much of what type of information an examiner needs to make an identification--unfortunately there's no simple answer for that. Fingerprints aren't like DNA, there's no handy table of X allele plus Y allele times population data, so there's no neat way to quantify it. On this topic, my pet peeve: When characters on TV say "It's just a partial." Unless your perpetrator stood at the crime scene and rolled his fingertip over something, from one edge of the nail to the other, then EVERY latent print is a partial!

Do fingerprints contain DNA? And if so, then isn't fingerprinting kind of obsolete, since you can just test the DNA instead of the print?

Asked by Sascha over 7 years ago

The skin cells sloughed off and left in a fingerprint contain DNA, but there's no guarantee that there will be a sufficient amount to obtain a DNA profile so it's a risk to go straight to DNA testing instead of developing the fingerprint. Besides, identical twins will have the same DNA but different fingerprints.