If a cop is mistaken in his belief that X is true, where X would typically be grounds for reasonable suspicion, does he have reasonable suspicion?

Question

If a cop is factually mistaken (but sincerely mistaken, not a liar) in his belief that X is true, and if X would typically constitute grounds for reasonable suspicion (were it to be true, which it isn’t), does the cop have reasonable suspicion?

Example:

A cop pulls a driver over because he thinks the driver turned right without signaling. The cop smells something strange, conducts a search, finds a crack pipe, and arrests the driver. Dash cam footage from the cop car is later reviewed, and shows that the driver did in fact use his turn signal properly when turning.

Did the mistaken cop have a "reasonable suspicion", and thus, grounds for pulling the car over? Is the crack pipe admissible as evidence?

A Spicier Example:

A cop thinks he hears a woman screaming from inside a house, repeating the phrase, “Help! They’re stabbing me!”. He calls for backup and has the house surrounded. Officers enter the house and find it completely empty, other than a small meth lab in the basement.

They find no people in the house, no amplification devices, and absolutely nothing capable of producing the sound of a woman screaming for help.

Witnesses who were standing next to the cop are interviewed, and all report that they heard nothing. Digital forensics experts later conclude that the officer’s body cam audio shows no traces of a woman screaming, and that there is no way a normal human ear placed within three feet of the camera would have heard anything other than silence.

There are fingerprints all over the equipment in the lab. They belong to the owner of the house.

Did the cop - provably mistaken in his sincerely held belief that there was a woman screaming for help - have reasonable suspicion that a crime was being committed, and thus, grounds for entering the house, admitting the meth lab into evidence, and arresting the owner?

Would the answer be different if the cop’s medical history was deemed admissible, and it turned out that he was a schizophrenic with a history of hearing voices?

Answer 1

A fact cannot by itself constitute reasonable suspicion; the word "reasonable" describes not only the relationship between the fact and the possible existence of a crime, but also the officer's knowledge about the fact. The officer must not only sincerely believe the truth of the facts constituting reasonable suspicion, but must also reasonably believe it.

I do not know whether a hallucinatory experience may be found reasonable for this purpose; I suspect that it would be a matter of dispute at trial. The first example is perhaps more straightforward, as there are probably a few possible explanations for the officer's failure to notice the turn signal. Still, are they reasonable? If the officer could not see the turn signals because something blocked the line of sight, it would not be reasonable for the officer to conclude that the driver had failed to use the signal. Rather, the officer has no evidence one way or the other, and absence of evidence is not evidence of absence.

The question deals in hypotheticals, where we can assume that the officer is sincere. But in a trial, the jury (or judge in a bench trial) cannot do that. They will look at the evidence, including the officer's testimony, and assess the officer's credibility. They will form an opinion about whether the belief was sincere and reasonable before they look at whether the facts, as the officer believed them to be, reasonably indicated that a crime was being committed or was imminent.