Wednesday, May 21, 2008

Citizens' Police Academy: Field Trip to the Crime Lab

By Annette Dashofy

This week’s instructors opened the class with a question: How much of what you see on the CSI shows do you think is real? I, of course, having studied Lee Lofland’s book, knew the answer was “almost nothing.” In fact, cases are lost because people expect things to be like what they see on TV. They have a name for it: “The CSI effect.”

In Pittsburgh, the guys who go out and collect evidence are called the Mobile Crime Unit. While they collect all kinds of evidence, Pittsburgh Crime Lab only processes fingerprints. Blood, DNA, or ballistic evidence is sent to the Allegheny Crime Lab or the State Police Crime Lab for processing. Unlike TV when DNA results come back in ten minutes, the truth is it takes eight weeks to get results. And then the report doesn’t come back to the Mobile Crime Unit. Instead, it goes to the detectives on the case and THEY make the arrest. MCU guys don’t do that stuff.


On TV, when a fingerprint is sent to AFIS, the results come back with a photo and address of the person matching the print. In reality, while results may or may NOT come back quickly, what the crime lab gets is a list of potential matches and all they get are numbers.


They look up the name belonging to the numbers on another computer. And a human eye is required to make the definitive match.

Different detectives have different specialties. So it takes more than one or two detectives to process a crime scene.

In Pittsburgh, all members of the MCU are police officers. In Allegheny County, crime scene people are civilians and work as part of the Medical Examiners office, not the county police.

A few more fallacies you will see on television:

Video surveillance footage does NOT get clearer when you zoom in. It actually is very difficult to identify a license plate, the color of the car, or the identity of anyone on the tape.

Only 7% of firearms are found to have usable fingerprints on them. In fact, lifting fingerprints isn’t nearly as easy as they make it look on CSI. A smooth, shiny, clean surface is needed to get a clear print. Drawer handles won’t usually work. Too small. Textured surfaces won’t work either. And door knobs have just too many prints to be helpful.

While DNA can be gotten from just about anything, it’s not cheap, costing $6,000 to $7,000 per test. Fingerprint analysis only costs the officer’s time.

Speaking of DNA, the question was posed to us, which is better: DNA or fingerprints? Think about this…identical twins share the same DNA, however, they would have different fingerprints.

When swabbing for DNA, the detective would swab twice. First with a swab dampened with deionized water. Then a second, DRY swab would be used on the same spot. The water brings up more DNA. Gloves would be changed before moving to another spot. The samples would be labeled BS1 (Blood Sample 1) for the first and BS2 for the second and so on. A sample would be taken nearby as a control sample (CS1) to identify contaminants.

We got a chance to tour the Crime Lab, which isn’t nearly as high-tech and shiny as those on CSI.


We were given a demonstration of Luminol, sprayed on a jug smeared with visible blood and a plastic bottle with nothing visibly evident on it.

The first attempt failed when nothing happened. Lesson? Luminol has a short shelf life. There are different types of the stuff and the particular kind being used had to mixed and used within hours. A fresh batch revealed luminescence on both jugs when the lights were turned out.

Note: it doesn’t glow very long. It doesn’t have to. Once the presence of blood is revealed, the detectives would simply collect the sample. And Luminol really does show the presence of blood even after attempts to clean up the crime scene.

A demonstration of an alternative light source that shows different materials unnoticed by the human eye also proved fascinating. Different colored goggles or camera filters are needed to see different substances.


We wrapped up our visit to Police Headquarters and the Crime Lab with a class photo.

That’s me in the back row, second from the right. Fellow Working Stiff Gina is sitting front and center.

Our stint in Citizens’ Police Academy is winding down. We have off next week (Memorial Day) and only have one more real class before our graduation. I’m feeling a huge sense of regret to see it ending.

What WILL I blog about???

14 comments:

Gina said...

Annette -
You left out the gross part. Our instructors offered squeamish participants the opportunity to leave the room before showing photos of what they really see at crime scenes: decomposing and dismembered bodies. Annette and I both stayed. They also presented a short video they'd prepared for Take Your Kid to Work Day that presented an overview of their activities, including processing a burglary scene and picking up blood stains from a car. And the official class photo was taken by one of the guys who photographs crime scenes, maybe the same one who took the above-mentioned corpse shots.

Annette said...

Gina, there's a lot I left out. I could write pages and pages on ALL our experiences.

They did give us plenty of warning about the pictures they were about to show, saying they would bother us for several days to come. Maybe I'm really weird, but they didn't bother me that much. Maybe because I worked on an ambulance for five years and saw a lot back then. You learn to separate your feelings from your thoughts or you'd never be able to do the job. The detective even mentioned that, plus how they can stand off to the side and laugh about something. It may SEEM insensitive, but it's a coping mechanism that I remember well.

I admit, I was extremely glad they did not have smell-o-vision, though. THAT'S what used to do me in.

Annette said...

And to anyone who read the blog earlier this morning, I am, in fact, second from the RIGHT, not left. I've since gone in and fixed it. (sigh) Dyslexia mixed with sleep deprivation is a bad thing.

Joyce said...

Nice summary, Annette!

Most photos don't bother me, either. We had a badly decomposed body a few months ago (that someone found in their basement)who didn't look all that bad in the photos. From what I heard, though, those at the scene had to actually throw their clothes out--they couldn't get rid of the smell. The one that bugged me was when a car fell on a young guy. He had the car jacked up on a stack of wood--not the brightest move. The wood shifted and the car fell and crushed him.

brenda said...

It sounds like CSI is actually science fiction as much as crime drama. Interesting.

JennieB said...

I'd have left the room. Very squeamish. When I needed a less than fresh dead body for my first book, I made damn sure I didn't see any pictures of decomposing bodies when I did my research, and I set the scene in pitch-darkness so my protagonist wouldn't have to look at it, either. That way I wouldn't have to describe it. The smell, though - that I know.

Sounds like it's been an interesting experience. Maybe I'll see if they've got such a thing down here. Or maybe not... the pictures, you know!

Wilfred Bereswill said...

I'm hoping to go through either the local police citizen's academy or the FBI acadamy.

In our last Sisters in Crime conference we had the head of the St. Louis County Police Crime Lab give a talk called CSI - Fact or Fiction. It was informative and funny.

Good stuff, Annette

Kathy Sweeney said...

I'm going to miss your classes too!

I have a friend in computer forensics and all these alphabet shows drive him batty. And you're right - juries now expect the kind of evidence that doesn't even exist!

Annette said...

Ah, the smell. Yes, Jennie, that's hard to miss and impossible to forget. And, Joyce, the detective said basically the same thing about the clothes. He said he would come home from a bad one and his wife would tell him she could smell death on him. And not just the clothes. It sticks to your hair and your skin and you can't get it out of your own nostrils. Yuck.

Think I'll step outside and sniff some lilacs. Or honeysuckle.

Annette said...

Brenda, you're right about CSI being sci-fi. But then again, medical shows aren't exactly accurate either, I can tell you.

So why is it they can get away with taking great liberties and call it creative license and we writers catch so much flack if we get the smallest detail wrong?

Donnell said...

Annette, as always fascinating! And I'm sure you'll find something else to blog about. Here's a question for you: When I did the citizens academy our cops said that on CSI they spread luminol like water ;) but in real life it's very expensive and not used as much. Did your crime scene lab address this issue. Very interesting on the shelf life. Thanks for sharing your experience. I suspect it will take your already-excellent writing to a whole new level

Annette said...

Donnell, the detective mentioned that they purchase the stuff from various sources, depending on the price. His favorite brand is the stuff in the spray bottle in the picture, which is called Blood Hound and apparently can be bought in sporting goods stores. Hunters use it to help track deer. My deer hunting husband has never heard of it. But he says it's probably an archery hunting item.

Anyhow, that was also the stuff that didn't work!

I never realized that it's something that you mix up just before using. The detective looked like he was mixing a cocktail.

Annette said...

Okay, did a quick Google and found this link:
http://www.westernhunter.com/Pages/Vol02Issue28/product.html

Anyone want to buy some and play CSI? No, I'm not volunteering to donate the blood sample.

Lise said...

Fascinating information. I especially liked the details about Luminol. I try to give the cop shows, just like medical shows, a bit of a break, however, when it comes to facts. I think they play to a certain extent into what they know to be "common" knowledge among viewers (even though the common knowledge is incorrect knowledge!!!) so as not to confuse everyone. And it is, after all, art, not life. I think the opportunity you guys had for the police academy "citizens" course of study looks great. I don't expect that the NYPD has anything like it, but I'm going to look into it! Thanks for sharing.