DNA trickery - has this plot device ever been used in a crime story?

When DNA testing first became popular as a forensic method, I, inspired by Hitchcock’s movie The Wrong Man, thought that this could be made into the plot of a crime story (I was reminded of it by this news article: Who’s Your Daddy? Paternity Battle Between [Twin] Brothers - ABC News)

My plot:
A man (or woman) who is adopted does not know that he (or she) has an identical twin brother (or sister) - could include triplets or quadruplets for more confusion.

The person is accused of a crime (murder, rape) and DNA testing proves conclusively that the accused is the criminal. Of course, at the end, the truth is revealed. The twin who actually committed the crime could unknowingly benefit from the confusion, or else could use the DNA match to his (or her) advantage and commit the crime leaving clues pointing to the genetically identical sibling.

I would be surprised if this has never yet been used, but I can’t recall ever seeing or reading it in fiction. Does anyone know of an example in a novel, short story, movie, television show?

Saw something like this on a recent CSI episode (forgot which one). And there were actually triplets as I recall. Part of the plot was how could one person be in two places (one place had the DNA) and then the cops need to figure out which of the triplets actually did the murder.

I hazily remember an episode of either CSI or Without a Trace where there were two identical twins - either of whom was in a position to have committed the crime (some murder or rape or something gruesome). The hitch was the DNA evidence could only prove that one of the twins committed the crime - not which twin. Thus, the DA could not prove beyond a reasonable doubt that one twin committed the crime and the other twin did not. So the culprit got away with it.

Something like that.

There was an episode of Law & Order that used such a device–

a guy was accused of murder based on DNA evidence, but actually his twin sister did it. Turns out she was born male but a botched circumcision meant she was raised as female.

I’m surprised by the cut-and-dried assertion in the article that twins cannot be distinguished by their DNA-- I was under the impression that even though the genes are the same, the methylation patterns diverge over time.

Straight Dope Staff Report on the subject. Doesn’t discuss whether they diverge over time, and I’m in way, way, way over my head! :wink:

Which book was it? It was a Kay Scarpetta mystery.

The killer turned out to have gotten a bone marrow transplant from a sibling, so that the DNA in the blood he left behind wasn’t his DNA. Not quite a twin problem, but I thought it was a nice DNA twist.

Wasn’t the Evil Twin already a hoary old cliche even before DNA evidence? I don’t see that genetic testing really brings anything new to the cliche… The point is that twins can be mistaken for each other, and that’s true for superficial appearances and DNA testing alike.

Are you thinking of the SVU episode? Cause it doesn’t go quite like you have in the spoiler. It wasn’t so much that the twin sister did it as it was they couldn’t tell which one did it, because they kept their back to the security cameras (the sister, from hormone therapy, still appeared feminine,) and obviously all the DNA matched both, and both used the alibi of seeing a movie with the other. Since they knew they couldn’t get one to rat out the other, they had to let both go free.

I recall a scifi story from Analog where DNA evidence led them to a group of clones; they were sure one of them did it , but couldn’t tell which.

This is essentially non-responsive, but the DNA matching issue came up in Jodi Picoult’s Perfect Match. Nary a twin in sight, but if I recall correctly, the villain had gotten a bone marrow transplant due to leukemia (??) so his new DNA didn’t match his old DNA.Been a while since I read it, though, so I could be waaay off.

Also, not fictional, but this story is about the failure of DNA to pinpoint which twin is the father and therefore liable for child support. Not a “crime story” but interesting nonetheless.

This is my thought as well. However, I could think of other ways DNA evidence could be used to mislead. I have a vague idea for a Law and Order or CSI plot in which the killer plants the semen of another man, disguising a simple murder as a rape-murder by a different assailant. The trick of course is how he gets a sample of the other guy’s semen, but there’s a few possibilities – e.g., the killer works at a fertility clinic. (Some of the more obvious possibilities might be ruled out by the fact that the killer doesn’t want the sample contaminated with his own DNA.) Perhaps the real killer would even end up being a woman.

I feel like a bit of a sicko for dreaming this up, but the way they always seem to instantly let the suspect go after discovering his DNA doesn’t match really begs for this sort of twist. Of course, with the multitude of cop shows on TV it wouldn’t surprise me to learn it’s already been done.

Not quite the trickery that the OP suggests, but more or less related. The J.D. Robb book Origin in Death features clones. So the woman suspected of murdering one victem is in custody (or a known public place) when the next victem is murdered.

However, the clones know about each other–although other people do not know about the clones, and I’m pretty sure that any DNA clues that were left were inadvertant.

A complete tangent but in Canada there was a doctor who raped a patient then planted a tube with another man’s blood in his arm to foil DNA tests. Sounds like the plot of a bad movie but it happened.

Article on Wiki Here I’ve always been fascinated by that case.

It has. This is essentially the premise of Scott Turow’s Presumed Innocent.

To coin a phrase, it’s a fairly dull and predictable plot turn, tedious, unoriginal, and lacking in any true insight.

I would like to thank you for using the terms ‘botched circumcision’ and ‘cut-and-dried’ in the same post. Thankyou.

Has there been a story where someone framed another by getting thier blood from a donation (perhaps the framer is the phlebotomist, or works at the blood bank)


IIRC, it was actually the father, not one of the clone sons. The detective managed to break the clone wall of silence by letting them know they had a brother who was culled early on because he wasn’t “perfect” enough. At least that’s my memory from way back.

If you don’t care about getting a sample from a specific guy, you can get all the semen you want by visiting any urban park on a Sunday morning and collecting used condoms. What are the crime scene guys going to do with a test that shows semen from two dozen men?

(Yeah, it’s gross, but if you’re trying to get away with, say, rape, it’s a safe presumption that your personal behavioral threshold is already out of whack.)

As long as the discussion has turned to planting DNA evidence . . .

I read a mystery* once where the murderer framed her husband. She obtained a sample of his semen and injected it into the woman she murdered. This confused things, because the murderer used spermicide to prevent pregnancy, and the murdered woman had had her tubes tied. The murderer also planted a glass with a fingerprint on it at the crime scene. The man who was framed had had an affair with the woman who was murdered.

Legal thriller? The man who was framed was the main character/point of view character. It probably wasn’t written by Scott Turow*, but (I think) he’s the kind of author who wrote the book I’m thinking of.

**I’m wrong, It was written by Scott Turow, and was called Presumed Innocent.