Will DNA evidence be worth anything in the near future/soon?

Poking into one of the central plot points of a recent Law and Order: SVU episode led me to this New York Times article about easy it is to fake DNA evidence.

Is this cornerstone of modern criminal justice going to tumble? What are the chances it’s already been used to falsely convict (or acquit!) someone?

From the linked article:
You can just engineer a crime scene,” said Dan Frumkin, lead author of the paper, which has been published online by the journal Forensic Science International: Genetics. “Any biology undergraduate could perform this.”

Dr. Frumkin is a founder of Nucleix, a company based in Tel Aviv that has developed a test to distinguish real DNA samples from fake ones that it hopes to sell to forensics laboratories. *


If I wanted to sell silver bullets, I’d tell you how dangerous werewolves are.

Nearly all crime is the result of passion, accident, or drunken/drugged idiocy. The number of cases of premeditated, planned out murders is negligible, regardless of what you see on CSI.

The problem with this sort of thing is that it require a lot of forethought and know how. The majority of criminals are stupid and reactionary.

Second, DNA evidence is not used in the majority of cases, and is usually not the only, or even the most compelling piece of evidence.

Lastly, in order to frame someone, you need a sample of their DNA from hair, etc. If you already have that, you can just plant that instead. Why go through the hassle of faking it when you have the real thing? While there probably are circumstances where blood is better than saliva or hair, it doesn’t make this a rational thing to do in most cases.

This. Even if they aren’t exaggerating how easy it would be ( and I doubt it ), most criminals who leave DNA evidence behind in the first place aren’t that clever. In fact, it’s already fairly easy to eliminate most DNA evidence; arson. If criminals were all that clever and careful about this stuff, they’d torch every crime scene.

Not at all. Cecil has a great article on arson and why it is so difficult to hide the arson itself. But many of the aspects that make it difficult to hide the arson also make it difficult to hide other crimes. Consider this BBC article from yesterday. The house burned down, but at the inquest they revealed that the boy was most likely smothered before the fire.

You are not wrong. If you want to kill someone, especially a random person it’s all too easy to get away with it.

Fire would still take out the DNA evidence, though. Hiding evidence of the crime itself is a separate issue, and if you do that properly, there obviously won’t be any DNA testing at all.

I guess my point is that it is difficult to guarantee that fire will eliminate all of the evidence without some sort of accelerant. The existence of accelerant might hide the original crime, but it will then give away that the fire was set deliberately and cause the police to look more closely at everything else. If you kill a person and burn down their house using accelerant, sure the body might be charred and the DNA gone, but the search for a motive for the arson will raise suspicions of murder. On the other hand, if you burn down a house without accelerant, the body might not get charred and any DNA on their body might be recoverable.

But maybe I am thinking of a difference scenario. Perhaps you mean someone that throws a body in an incinerator to destroy the DNA. In this case, they are not trying to hide the murder, just the murderer. In this case, then I agree.

Well, if the crook seriously think that nobody will suspect it’s a murder, why worry about DNA? They don’t test for DNA until they have some reason to think there’s been a crime, do they?

TV shows today vastly exaggerate the use of DNA in forensics. Both in how often it is used and simple it is to get results back in a timely manner.

For me, the unbelievable thing about that L&O ep wasn’t that a faked blood sample was possible. They have to do DNA amplification to do a DNA test on hair or the like anyway. What was unbelievable was that the ME had, on her own initiative and with no reason to suspect a faked blood sample, tested whether the DNA was methylated or not.