Major Question

I saw this movie when it first came out and really enjoyed it. While I still like it I was wondering how they could state Adrian was dead from suicide. What body did they have and how were they able to identify him from it? It may have been stated in the movie, but I do not remember it? Did he find someone who looked enough like him and the body decomposed enough so the authorities assumed it was him? The guy was a rich, genius authorities and influential people would make certain it was him?