If this was in my neighborhood it would be likely that the bike was stolen and ditched. I would want the police to take it out of my hands. But you know your own circumstances best and can evaluate the situation better than I can. Regardless of the specifics, I would be extremely hesitant. I had bikes stolen from me, one of them a Jan Janssen roadbike worth 1200-1400 euros. Probably part of the reason why I would not want any part in it.