How admissible is *smell* evidence in a court case?

General Questions
#1

I was just having my usual Monday morning random thoughts and got to thinking about the five senses and how sight and hearing seem to be the only senses that are accepted from a legal framework. And I then got to wondering, what kind of status do the other three senses have from a legal point of view, especially smell?

I mean, I am sure eyewitness testimony in a case would usually be something “I saw the defendant strike the victim” “or I heard the defendant’s voice coming from the victim’s room shortly before midnight”. But what if the witness testified that “When I found the victim lying in a pool of blood I could smell that the defendant had recently been in the room”?

Would this be admissible? Has this actually happened?

#2

It’s very common for police officers to testify “I smelled alcohol on his breath.”

So, yeah, I would say that testimony as to smells is admissible.

I think you’d have a hard time convincing a jury of this. If I were the prosecutor, I would be reluctant to put on that kind of testimony unless either (1) the witness could pass a smell lineup; or (2) the defendant had some kind of distinctive odor, for example he used BenGay every day.

In the latter case, the defense attorney would argue (correctly) that a lot of people use BenGay and you cannot establish proof beyond reasonable doubt without a lot more.

#3

I believe cops have been able to search vehicles and premises because they smelled pot. So being able to recognize certain odors is admisible as evidence to some extent.

#4

Nobody asks the police dog what he sees (nobody asks him much of anything, actually), and evidence of a K9 search is admissable.

#5

I was thinking more in terms of smell as a means for identifying a suspect, sort of the way a dog can. I mean, every person does have a unique scent, which dogs can identify, so what if a witness has a highly developed sense of smell as well?

And what if it was an artificial chemical odor, say an obscure expensive perfume. Even if you can’t say it is unique to the suspect, it could narrow things down a lot. For sight-based testimony, don’t witnesses frequently say things like "the person I saw fleeing the crime scene was a short thin white man wearing a red t-shirt and cutoff jeans’?

#6

It’d be hard convincing a jury that you could identify a person by smell alone.

This is more solid ground. If you could identify a perfume that the defendant habitually wore, that would be admissible, though certainly not conclusive. If there was a strong smell of oil in the room, and the defendant was shown to have just performed an oil change on his car, then it would also be admissible (though also not conclusive).

#7

I once talked story with a former federal prosecutor. He told me about a bank robbery trial he did in which all of the witnesses testified that the bank robber really stank. The defendant had a complicated story (alibi defense, IIRC). So the prosecutor set up a blackboard really close to the jury box :wink: so the defendant could illustrate his story. The prosecutor said that when he saw the juror’s eyes tearing up, he knew he’d won.

#8

The perfume thing used to be big in the noir style of mystery novel - “… and then I smelled it. That dame’s perfume.”

#9

Perhaps, but that is inevitably going to be followed up by the question “Do you see the person you saw fleeing the scene in the courtroom today?” for an identification by the witness on the record. Not sure how well “Do you smell that person in court today?” would work.

#10

Depends on whether he showered. :slight_smile:

But the testimony of a smell is unlikely to take that turn. More likely, the prosecution would establish that other people noted the person smelled bad that particular day and the witness had noted the smell before the crime was committed.