Is it possible to for one to get arrested if he or she was collecting money from someone he or she knew. The money in the question is "dirty money". Only collection of the money though, no transfer of drugs or other illegal contrabands involved.

Possession of stolen property/Proceeds of crime.

The money isn't stolen, but can you elaborate a bit more about the legalities of proceeds of the crime in America? I looked it up on google real quickly, and the information given involves a British legislative act in 2002. Let's set a limit on the amount of money also, say only at the most one thousand dollars.

Wouldn't they also have to go about proving that the money in question are from criminal activities?
Would it be possible for a snitch to set someone up in this situation to reduce his sentence?

I'm writing a paper about some some gangster movies (I got lucky and convinced my teacher to let me do so), so I need very clear information.

"In the United States, Federal law provides (in part): "Whoever . . . knowing[ly] . . . conducts or attempts to conduct . . . a financial transaction which in fact involves the proceeds of specified unlawful activity . . . with the intent to promote the carrying on of specified unlawful activity . . . shall be sentenced to a fine of not more than $500,000 or twice the value of the property involved in the transaction, whichever is greater, or imprisonment for not more than twenty years, or both."

It's been expanded upon through the Patriot Act I believe...