Title and Author

[SMP]

A friend has asked if iI can find the title and author of a book for him.
The story has a congregation in Hamburg Cathedral taking communion and those that eat the bread die.
All the entrances are sealed and the rest of the congregation are shot, all but one person who hides in the confessional.
The perpetrators are trying to steal the remains of a past pope that are buried in the cathedral.
They go on to the Vatican to try to steal the remains of another pope.
Thanks

[shaneystar2]

I can only think of James Rollins. Map of Bones .
But ..this takes place in Cologne Cathedral .The congregation are killed by assassins dressed as monks .They steal the bones of the Magi from the shrine . No Popes involved !

[SMP]

Thanks shaneystar 2 looks like this is the book.