Topic: Cujo

This is one of my favourite books of all time and i've read it so many times i've lost count but something about it has always confused me.

You know how he talks about the murderer Frank Dodd at the start of the book and about how his spirit returned and all that.  Also how Tad see's some evil presence in his closet.

Does this mean Frank possessed Cujo?? Because it does not tie together at any point in the story! He only talks about Cujo and from Cujo's POV having rabies and the symptoms of it.