Issei Sagawa - Killed a classmate, raped, and ate her body... but was not convicted, later becoming a lecturer and sushi critic in Japan

Did you read about it at all? His wealth wasn't relevant. France declared he was to be held indefinitely without trial and then deported him to Japan; Japan said no, he has to have a trial, and then France refused to hand over the case files.

Sounds like French laws are deeply problematic.