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CHICAGO (AP) A former deputy U.S. marshal is going on trial in Chicago for allegedly leaking secrets to the mob about a federally protected witness.

John T. Ambrose is accused of tipping off organized crime figures about admitted former hit man Nicholas Calabrese (KAL'-uh-brees).

Calabrese was the government's star witness at the 2007 "Family Secrets" trial that targeted top members of the Chicago mob.

The 50-year-old Ambrose, whose trial begins Monday, denies he ever broke the law in handling secret information.

Ambrose was assigned to guard Calabrese on two occasions when witness security officials lodged him at "safe sites" in Chicago for questioning by prosecutors.

Ambrose is charged with stealing information and passing it to a go-between, believing it would go to a mob boss.

(Copyright 2009 by The Associated Press. All Rights Reserved.) APNP 04-13-09 0441CDT | save this article / add to your favorites list