Found: A briefcase containing nearly $80,000 US in small bills in New York City. If it's yours, a Good Samaritan wants to know.

The classified ad, which describes in vague detail a briefcase full of money that was found in New York's Lower East Side, was posted early Sunday morning on the popular classifieds site Craigslist.

"If you can describe the other items inside I will return," writes the poster. "If not I am taking to the police and after no one claims it I think I can legally own this."

According to New York State law, anyone who finds property valued at over $20 US, including cash, is obliged to seek out the rightful owner, or turn it over to police so they may do so.

For sums greater than $5,000 US, police will hold on to the money for three years and ten days. If, after that time has passed, nobody has come forward as the rightful claimant of that money, the person who found it will be declared the owner.

But even then it's not so easy. If the briefcase was found in a privately owned establishment like a restaurant or a bar, the owner of the property can also claim ownership.

Either way, the anonymous Craigslist poster now has three years to figure out what he could do with $78,383 in cash, and a new briefcase.