The Bishop and the Three Kings — Andrew M. Greeley

It's a chilly October morning in Cologne, Germany, when a major relic of the Catholic Church, the remains of the Three Kings, is stolen from the cathedral! When the theft becomes public it'll be a cold day in Cologne, for the resultant furor could have dire political and religious implications worldwide. That is, unless Bishop Blackie, already far from home, can journey even farther to track down the thief and his plunder. But as each lead brings on greater dangers, even a detective like Blackie could use a miracle to bring back Cologne's most prized relic...