7 Bullshit Police Myths Everyone Believes

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#7. Forensic Science is Magic

As Seen On:

The various CSI shows, Bones

Typical Scenario:

There has been a murder. While the regular cops are all wasting time talking about "witnesses," "motives" and "evidence," the CSI team walks in and gets shit done. Within seconds they find a single hair, scan it with a green laser and discover the identity of the killer, saving countless lives with their ingenious magical science. Hell, the CSI team will even pack up their guns and go arrest the guy!

Why it's Bullshit:

First, do you have any idea how much random DNA you are carrying on the soles of your shoes this very instant? A hair from that bank clerk across town, gum from a Pakistani cab driver and semen from an undetermined source are all probably crawling around down there, ready to be tracked through a crime scene.

Also, certain laboratory tests such as DNA samples, toxicology and blood reports can take weeks or even months to process, and when they do finally arrive, they are about as clear cut as the plot to The Phantom Menace.

Also, while DNA criminal databases do exist, less than 1/10th of all criminals are a part of it. Having a bit of DNA doesn't mean shit unless they have something to compare it to.

That means the CSI stuff is less about finding the killer and more about making sure they have enough evidence to convict the guy they've already pinpointed as a suspect through old-fashioned police work.

CSI is really just another victim of bad Hollywood science, kind of an extension of their "computers are magic" philosophy. It's appealing to think that any problem--even crime--can be stopped cold by nothing but the power of science and human intellect. Add a few dead hookers and an exploding car to the mix and you have the recipe for television success, baby.

in Wired a few months ago. About the CSI crap. It isn't based on science at all, for the most part. It's just stuff cops came up with over the years. But there's actually no scientific basis for even something as basic as fingerprints.

Jurors, having seen shows like CSI, are fully expecting the same kind of "evidence" when they are seated at a trial. When they discover the real world isn't like TV, there's quite the disconnect.

I think the most ridiculous thing I ever saw on one of the CSIs (and what made me finally give them up for good) was when they used a grainy security camera photo to extract the image of someone offscreen by detected their reflection in a guy's eyeball.

I could accept the photo manipulation in Blade Runner; after all, it's science fiction and set way in the future. Who knows how good photography will get, and how the resolutions will be? But this was just ridiculous.

Yes! They do this all the time. They enhance and clarify images in which the resolution just isn't there. Sure, there's a lot that can be done with interpolation and NASA has some amazing interpolation algorithms that can allow it to massage raw digital camera shots into amazing photos that reveal a lot about their subjects. But if the information isn't there in either the source pixels or the surrounding pixels, it's just not there.

Even worse, is that most cheap digicams these days have pixel resolutions so high that the pixels are actually smaller than the wavelengths of light they're capturing. This means those $100 12MP point and shoots are just capturing noise in all those extra pixels. That's why a shot from a high end 5MP digital SLR can be much better than a pic from a low end 12MP point and shoot. The CCD sensors on SLRs tend to be much larger than those on point and shoots, thus the individual pixels are actually capturing information not noise.

So when the CSI shows take a slow speed, low resolution security cam with a crappy plastic lens and enhance the hell out of it to see a reflection in somebody's eyeball or a pic from some tourist's point and shoot to get the picture of the murderer from the reflection in someone's sun glasses, it's not even science fiction. It's just pseudo-scientific bunk.

I think of 24 that someone was groaning about so I had to watch (I was barely able to finish watching it it was so bad). It was about a smallpox outbreak from a box labeled "Variola Major Samples" stored in a commercial storage facility that someone had broken into. That's a big eye roll right there, having been involved in shipping and receiving select agents (which smallpox is). At some point in the show, a blood sample was observed under a LIGHT microscope where the virus was *bigger* than the RBCs, was in full color, and the strain was identifiable by microscopic observation.

Expert witness testifies: "We took an empty jar six miles due south of the crime scene, 15 minutes after the victim was killed. We took a sample of the air and found molecules in it that were also present on the defendant. Our compure model shows that the only way they could have gotten there is if they were carried from the exact scene of the crime on prevailing winds. Therefore, we know he's guilty."

And the jury buys it because they keep seeing this kind of thing on TV and therefore believe it's possible.

Lazarus' post #3 about the reflection in the eyeball is the kind of thing I'm talking about.

I'll need to track down the article, but the gist of it was that some jurors are now expecting airtight cases against the defendants, as shown on countless crime-scene shows. If the police can establish a second-by-second timeline of the defendant's whereabouts and actions on the night in question, then this can be leveraged to establish "reasonable doubt."

Hey, I'm all for demanding a standard of evidence, but there comes a point when thoughtful, reasonable people should be able to see a one-minute discrepancy in a three-day timeline and say "yeah, that's no big deal."

Amazing that people will believe some science fully (forensic) but doubt others (cosmology, evolution).

Maybe we need some TV shows with David Caruso about cosmologists and biologists.

It was never meant to be the entire investigation. There is some legitimate science behind it, but people don't seem to understand there's a thing called "error" that can render results questionable or meaningless.

I'll probably never get on a jury for a trial that involves DNA evidence because I understand the technology. Look at how they raised doubts on the blood testing because of a miniscule chance that the test was wrong.
That whole thing still makes my blood boil when I think about it. All that legit and good DNA evidence basically thrown away by the jury because of their ignorance which of course the defense took advantage of...:grr:

I bet if that trial were held today, OJ would have been convicted. Back then, it was a hell of a lot easier for high-paid defense lawyers to attack such evidence.

It's a double-edged sword; I'd say for about 80% of all cases, you don't even need forensics, and for what's left, it's only needed to provide weight to the prosecution's case.

Jury nullification is still a very successful tactic. And people are specifically chosen because of a lack of knowledge of this type of evidence by defense lawyers. I'm willing to bet there is a lot of voir dire questions aimed at seeing if one is a fan of CSI.

Even not knowing much about anthropology I can guess that some things are bullshit. One of my coworkers also watches is and we keep saying we want those giant TV screen to display our data and design experiments that blow things up. Mainly we can appreciate Brennan's social awkwardness as many of us share it. And Booth is a very lovely man!

http://www.zoklet.net/totse/en/law/justice_for_all/index.html

...only applies to SELF incrimination. There is no right to refuse to disclose information that incriminates someone else.