Horror book about James, brother of Jesus
 

I have been trying for some time to remember the name of a book I read in the 80s. The protagonist has many weird things happen to him and in the course of investigating learns that he is James, the brother of Jesus. Because he failed to protect Jesus when the soldiers came for him, James finds that he is cursed to relive the bad events in the book over and over for eternity. In the end of the book, he briefly meets Judas Iscariot, who was cursed with a much worse fate.

Does this sound familiar to anyone?

I found it!
 

I've tried to remember the book I described in the original post off and on over the last 30 years. Since the advent of the internet, I've searched for it many times, with no luck. Asking about it here sent me off on another long bout of searching - and I FOUND IT!

The book is The Shroud by John Coyne, published in 1983.

The main character's name is Jamie, and he's not James the brother of Jesus, but rather another brother, called Judas Thomas. Anyways, I'm glad I found it.