More possibsle situations now:
I'm thinking of the idea of our man being dependant on pills to treat something like depression or schizophrenia (damn, thats a long word) and maybe he could've forgotten to take his medicine. In which case it would make his dissappearance more of a concern
OR
How about one of the people who reports him missing lie to the police. Perhaps he/she could say that they suspect some sort of kidnap. (I know it's wrong to do stuff like that but hey, it's a story

)