Name this crime.

Assume that I make a piece of your property unavailable to you without destroying it. (i.e. I move you car keys to an undisclosed location on your property). What crime would this be?

obstruction of property implementation and the right to return

Why would it be a crime?

It’s a civil wrong for which you can sue - in Ireland I think it would be called conversion - but not necessarily a crime.

Depending on the precise circumstances, it could be theft or larceny of the car keys. But it might not be (if, e.g. I had given you the car keys and you simply refused to return them).

Black’s Law Dictionary defines conversion as, among other things, “Any unauthorized act which deprives an owner of his property permanently or for an indefinite time.”

Conversion is a tort, not a crime (in the US as well as Ireland, as UDS states).

Well, since the car keys are property, I’m sure it would count as plain ol’ stealing as well, wouldn’t it?

As I pointed out in my earlier post, it might or might not be theft of the car keys, depending on what exactly you have done or not done with the car keys, and what the elements of “theft” are in the local criminal law. It is certainly not theft of the car.

It depends on your intent, and the more specific facts of the taking. Let’s say you take them without permission from the person’s desk at work, without their consent or with their consent obtained by fraud, and further that you intended to permanently deprive the owner of them. You are guilty of larceny.

On the other hand, if you were holding the keys in trust for the owner and “converted” them to your own use in a manner inconsistent with the arrangement by which you held them, with no intent to restore the exact property, you are guilty of embezzlement.

If you instead gained not mere possession but actual title to the keys by an intentional misrepresentation of past or exisiting fact with an intent to defraud the owner, you are guilty of false pretenses.

If you take the keys from the owner’s person or presence by force or threat of immediate death or physical injury with the intent to permanently deprive the owner of them, you are guilty of robbery.

This is all at common law, meaning in the abscence of any modifying statute. Some US states combine and define some or all of the above crimes into the more general crime of “theft”.

You also may be guilty of the torts of trespass to chattel or conversion, even without the intenet to permanently deprive the owner, depending on the seriousness of the interference with the owner’s property rights.

The tort would be detinue rather than conversion IIRC. A refusal to return the keys would make it conversion.

It’s called being a jerk, which is grounds for getting banned.

Oh, you mean in the real world? Dunno. Sounds like theft while the keys are in your possession, conversion when they aren’t, and, probably, trespassing.

It can be both the crime of theft and the tort of conversion, or one or the other, or neither. You can commit larceny without conversion, you can commit conversion without larceny. Whether or not the keys are in your possession are immaterial for larceny. If you put the keys in your pocket intending to deprive the owner of them, then think better of it and put them back, you are guilty of larceny by the mere taking (“asporation”) regardless. If you take the keys thinking that they are yours and destroy them, you are guilty of conversion but not larceny since you didn’t intend to deprive the owner. If you return the keys on immediately discovering that they aren’t yours, you haven’t significantly interfered with the owner’s possession, and aren’t guilty of any crime or tort. Taking the keys and hiding them may several different crimes or torts, depending on how you came into possession of the keys, whether you intended to deprive the owner of them, and how significant your hiding them was in interfering with the owner’s possession.

What tort you have committed depends on how significant the interference with the owner’s right to possession, and whether it’s an action in detinue, replevin, or trover and conversion would depend on whether the original possesion by the wrongdoer was lawful or unlawful, and whether you want the property returned or money damages paid (a “forced sale”). These terms are archaic in the U.S.