Several weeks ago in Evidence we were discussing case out of California. The case was from the mid-1960s and involved a young woman who had been brutally murdered. Underneath her body were found the bottom halves of a pair of silk stockings, recently worn. Her legs, when she was found, were bare. Interviews with people who had seen her earlier in the day revealed that she had been wearing a pair of stockings similar to the ones found underneath her.
The investigation eventually led to a young man. The police obtained a warrant to search his apartment. Inside his dresser drawer were found the tops of several pairs of silk stockings, the bottoms having been torn off. Three more pairs of stocking tops were found hanging from the curtain rod in the bathroom. The man was arrested. Forensic examination revealed that none of the stocking tops in the man's possession matched the stocking bottoms found under the victim; the stocking tops did not physically tie the man to the murder.
The question posed to the class was whether the stocking tops could nonetheless be presented as evidence at trial. Students were called upon and, in the professor's usual aggressive style, arguments for both sides were coaxed out of them.
One of the basic principles of evidence is the balance between relevance and prejudice. A crime or a cause of action has elements that need to be proven. Relevance is a measure of how much a piece of evidence tends to prove (or, in the case of the defense, disprove) one of the elements. Prejudice is a measure of how much a piece of evidence will sway a jury to vote one way or another for reasons unrelated to the elements at issue in a trial. The tricky part comes when a piece of evidence is both relevant and prejudicial. There the question of whether to allow the evidence turns on whether its probative value is outweighed by its tendency to sway the jury for the wrong reasons.
So: The stocking tops. They're not a direct physical link to the crime scene. So they're not strongly relevant. They're still fairly relevant, though. We can be fairly sure that the killer was someone who collects stocking tops. The defendant collects stocking tops. That's pretty good circumstantial evidence in favor of guilt. You probably couldn't convict solely on the basis of the stocking tops, but it would help the prosecution's case.
After extracting this analysis from a succession of students, the professor turned to the next person on his list.
"So, Mr. Blank, you're representing the defendant. How do you keep these *stocking tops* out?" (Wherever I put the words "stocking tops" in quotes, imagine the professor rapidly switching from a bombastic mode to a tip-toey, exaggeratedly salacious tone)
"Ummm... I guess I would argue... that they're prejudicial?"
"Very good! And what's so prejudicial about *stocking tops*!" (Here the professor raises his eyebrows suggestively)
"Ahhh... They... don't really tie the defendant to the crime scene?"
"No, no, that's about relevance. I want to know about prejudice? Why would *stocking tops* be prejudicial?"
"Well, they'd make the jury think they were more significant than they are."
"Maybe I haven't made prejudice clear. Prejudice is about making the jury convict for reasons unrelated to the crime. So, I ask again, what's so prejudicial about *stocking tops*? Why would *stocking tops* make the Jury dislike the defendant?"
"Well....Ummm......"
"BECAUSE HE'S A PERVERT!!!"
At this point I got a little bit nervous.
"NORMAL men don't collect STOCKING TOPS! They don't even collect STOCKING TOPS in CaliFORnia! Show of hands! What men here are from CaliFORnia?"
I nervously raised a hand to about shoulder-height from my seat in the back row. The professor called on a guy in the middle benches.
"You're from CaliFORnia? Tell me: Do YOU collect STOCKING TOPS?"
"No, sir."
"See? They don't even do that in CaliFORnia! You want to win this case, you have to keep those stocking tops out! You have to argue that if the jury catches one sight of those stocking tops, they'll instantly convict your client for being a pervert without looking at the murder trial!"
I am, in retrospect, glad that I didn't get called on. Had that happened, the dialogue would have gone a tad differently:
"You're from CaliFORnia? Tell me: Do YOU collect STOCKING TOPS?"
"Just the tops? No, I don't collect just the tops of stockings."