Other mistake: There are two mistakes with the ambulance that arrives on the scene to retrieve Jason's body. First, the letters that are supposed to spell DODGE on the front of the ambulance are missing the first D. Second, where is the reversed sign saying AMBULANCE that all ambulances are supposed to have in case people see it in their rear view mirror?
Other mistake: Rob's articles talk about a murder at a cafe. The murders took place at a small grocery store.
Chosen answer: He's not possessed. Dealing with Jason made him go crazy. In part 5, we find out he was in a mental hospital for a while, then gets sent to a home for troubled kids.