livedarklions

Given the outcome, the most likely explanation to me is that the bike purchaser let himself get conned into believing a too-good-to-be-true deal was legitimate (suspension of disbelief in order to get a big payoff is how a lot of scams work--e.g., the lottery scam, a lot of people convince themselves they actually forgot they played the lottery they supposedly won). Obviously, once he knows it's stolen, it's absolutely worthless to him unless he's willing to risk being charged with a crime himself--he can't ride it because if he's caught with it, he's in possession of stolen property and he can't sell it as selling stolen property is itself a crime. If he stole this or bought it knowing it was stolen, I don't think there's any way he would have agreed to dropping it at the police station because the obvious way to ditch the stolen evidence if that was his only concern is just to discard it somewhere, like literally throw it into a ditch. The simplest explanation for why he brought it to the police station is he wanted to correct the harm caused by his mistake.

Do you know whether they gave the police a statement as to how they got the bike?