How undercover cops get suspects' DNA

Aaron sez, "This piece from the LA Times includes a stunning description of how an undercover cop lifted a DNA sample from Stephanie Lazarus, a police woman was under investigation for murdering her romantic rival."

An undercover officer surreptitiously trailed Lazarus, 49, as she ran errands, waiting until she discarded a plastic utensil or other object with her saliva on it. The DNA in her saliva was compared with evidence collected from the murder scene. The genetic code in the samples matched conclusively, police and prosecutors have said.

And this is one of the main reasons that biometric identifiers are so very risky... You can protect the PIN for your debit card by shielding the keypad when you enter it, but how do you keep counterfeiters from getting your DNA for authenticating the debit-card of the future? We throw off fingerprints, DNA, hand-geometry impressions, gaits and other biometrics at a titanic rate, and there's no way to stop, short of spending all your time in a hazmat suit.

Bail is set at $10 million for LAPD detective accused of murder (Thanks, Aaron!)

(Image: DNA Molecule display, Oxford University, a Creative Commons Attribution photo from net_efekt's photostream)

Previously:

I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.

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Piers W

Absolutely right. I hope it prejudices the police case. If they routinely follow people around to get DNA to ‘match’ a crime scene, they also have the capability to follow them around in advance, collect DNA and plant it.
Anonymous

I’m waiting for smart criminals to begin planting misleading DNA at crime scenes. In fact, I’d be stunned if it wasn’t happening already. Two weeks before the crime, gather some DNA tainted objects from a likely suspect for your crime, and on the day of the crime, smear their DNA judiciously about the scene. Viola! Instant fallguy.
Anonymous

It means I can steal a few strands of hair off your Brush and leave them at a crime scene.Thus framing you.
Neon Tooth

Is this a surprise to people? They do this in like, every episode of Law & Order ever. They’re always going through peoples’ trash for tissues or hair or picking up cigarette butts that suspects have discarded.

Ha yeah,
I was just going to mention that they show this on some of the various tv cop shows. specifically thinking of one where they go the dna off a discarded paper coffee cup..
Anonymous

It would have been far quicker and far less expensive to just have the undercover cop work the back of the trash truck and snatch a bag of her garbage. Females tend to throw things out once a month that are pure DNA samples.
cuvtixo

For people afraid of law enforcement (or biohackers?) or invading some expectation of “biological privacy” or forging DNA– Right now many, many guilty criminal judgments are based on eyewitness accounts (victims, “snitches,” and other unreliable witnesses.) As long as planting DNA remains more difficult to fake than it is for witnesses to be coached (and that’s amazingly easy)– DNA analysis will remain a vast improvement for the American judicial system. And the speculation about the use of biomarkers in the future for things like credit cards is wildly unlikely. Lay off the eggnog for a bit, Cory. ;)
ackpht

Not to mention the trail of skin flakes and hair that we leave on everything we touch.
Zadaz

When wireless digital cameras can be 1mm sq in size, simply covering my hand as I enter a PIN is not going to cut it.

This is the thought that I had today as I entered my PIN while covering my hand in addition to the plastic “privacy shield” that was provided for me. There would be any number of places a camera could read my 4 keypresses that I wouldn’t notice.

So, whatchagonna do now? My DNA is everywhere, my PIN is snoopable. Are we back to a promise and a handshake?*

* For me my gut is still the most trustworthy of any validation scheme.
- Anonymous
  
  Zadaz, I trained myself years ago to include “false presses” in the entry of my PIN when I noticed kids hanging around the pay phones in suburban station shoulder surfing call codes. More recently I have developed a way to appear to press one button with my index finger while surreptitiously pressing an entirely different button with my thumb, hidden by my palm. Practice makes perfect.
  
  Incidentally, I’ve heard that not everyone expresses DNA in their saliva. Anyone know anything about that?
Anonymous

And if someone steals your PIN, you can change it. No way to change your fingertips, eyeballs, or DNA.
LiudvikasT

That’s just horrible, police trailing a suspect to get a dna sample. It doesn’t matter that it matched, but it is still very wrong of them to do that. Getting a dna sample should be only with a warrant and only with suspects knowledge.
transiit

Spit in every trash bin you pass. Not to aid criminals, but to protect your privacy. Same reason I trade store affinity cards (“rewards cards”) with people as often as I can.
Lazlo Panaflex

the HAZMAT suit comment reminds me of A SCANNER DARKLY (maybe the police thing too) where the lead character has to wear a suit that completely masks his appearance. i guess i’m going to have to read that story now…
JayConverse

DNA sampling will one day become so cheap, that a cop will be able to pick up that empty soda bottle you through out of your car window, test it, and send you a littering ticket.
Snig

Can’t they just take a picture of the suspect and have their tech guy zoom way in, then “Enhance…Enhance…”

Or they could trick the perp into saying something like “suffering succotash” and harvest the spray of saliva from the air.

Their used to be stories (at least in fantasy, don’t know if it was ever practiced) of witchcraft where Kings had to keep their toenail clippings and trimmed hair safe, so it couldn’t be used for magikings.
- Anonymous
  
  See, that is why I keep all my poop in jars in my closet. I guess I have the last laugh over all those who think my policy is a waste of time.
Anonymous

“…the samples matched conclusively, police and prosecutors have said.”

Police and prosecutors say a lot of things that aren’t true. Their jobs often require them to do so. This woman may or may not be guilty as sin, but she has already been convicted in the court of outraged internet commentary.

DNA evidence today is still sketchy despite what we are led to believe(I blame the CSI franchise). That saliva from 1986(!) matches saliva from a plastic spork from a garbage can full of contaminated material in 2009 strains credulity.

By the way, if anyone cares, the trial has yet to occur.

Guilty? I don’t know. I do know she is innocent until proven guilty in a court of law.
mmbb

what if it was a wooden utensil, like a chopstick? is that fair game, since it is a utensil, not plastic, but not an “other object?”

reminder, kids, don’t spit on the street when you’re visiting singapore.
Anonymous

We have come to a time when a lot of retailer do not require either a pin number or signature crrying plastic is no safer than carrying cash. My debit card makes me responsible for the 1st $50. I checked that is the 1st $50 of each transaction untill I notice the card is missing and report it so my account can be cleaned out $50 at a time. We no longer bother checking signatures, a lot of cashiers can’t even make chage without the register telling them how much. We rely to much on the system we have set up so I guess we deserve what we get.
adamnvillani

You’re missing the really remarkable part of this story, which is that the LAPD investigated one of their own for murder.
- Piers W
  
  I see. Hope I’m not being overly suspicious in suggesting they might be messing the case up on purpose.
Anonymous

They just caught a guy in New York doing a pay-to-park scam using DNA from a can of soda he left behind:

http://www.nytimes.com/2009/12/19/nyregion/19park.html
Anonymous

In my wallet I carry a piece of paper with 6190 on it – but invert it and it says 0619. And neither of these is my actual PIN number. But it insures two WRONG tries right off the bat…
Mark Crummett

They’ve been doing this on CSI for years.
Anonymous

I worked on an Innocence Project while in law school. We had an man accused of murder (later appealed and acquitted) and a suspect who had been a suspect from the start. I met with him in a diner on the pretext that we just wanted his opinions on the conviction from years back. I made an excuse, he left, I kept his coffee mug. Do I feel bad about it? Not hardly. Turned out he wasn’t the person that there was DNA evidence from but it was a legitimate part of the investigation. Following someone around until they leave behind a genetic marker “clue” is not wrong. It’s good detective work.
smammers

Is this a surprise to people? They do this in like, every episode of Law & Order ever. They’re always going through peoples’ trash for tissues or hair or picking up cigarette butts that suspects have discarded.
Shaddack

JayConverse: Already being done with littering dogs.
http://uk.reuters.com/article/idUKLG37942520080916
greenup

Use authentication identifiers that you don’t leave around everywhere, but are still unique and secure.

Bad:
DNA
fingerprints
passwords on post-it-notes

Better:
Finger-vein patterns
passwords you keep in your head
LightningRose

All of your questions were explored in the 1997 film, “Gattaca”.

http://en.wikipedia.org/wiki/Gattaca
- Felton
  
  Good movie, and by reading that Wikipedia entry, I now know that there’s such a thing as biopunk.
Anonymous

retinal scans ftw!
- spool32
  
  Retinal scans aren’t terribly good for some situations. Example: pregnancy changes your retinal vein patterns. Apart from the privacy issue, it renders them inaccurate for 50% of the population.
GuidoDavid

[biopedantic mode=ON]
Genetic code is the way DNA is translated to proteins, it is the same in every single human being alive and has been the same for every mammal. The Genetic code cannot be used to identify people[biopedantic mode=OFF]