Possible Clues:

• Unbeliever present when robbery is committed
• I don't believe first letter's the first!
• One denying existence of a god
• One not believing in gods
• One beyond belief?
• A believer or otherwise
• One doesn't believe cook heats it
• One article after another is on rat's tail - but he doesn't believe it
• Nonbeliever in God
• A follower in the religious sense of non-believer