U.S. marshal arrested by FBI in mob tip case

CHICAGO -- A deputy U.S. marshal was taken into custody yesterday for allegedly leaking "highly sensitive, confidential information" to organized crime figures about a key witness in the FBI's investigation of more than a dozen unsolved Chicago mob killings.

John Thomas Ambrose, 38, was charged in a criminal complaint with revealing information related to "the status, substance of cooperation and travel" of Nicholas Calabrese, a defendant and key witness in the FBI's Operation Family Secrets investigation, according to a news release from the U.S. attorney's office. Ambrose made the alleged leak while Calabrese was in the federal witness protection program, the release said.


Ambrose, a marshal for nine years, was scheduled to appear before a U.S. magistrate at 1:30 p.m. He surrendered voluntarily yesterday to the FBI. He has been on administrative leave since last September, when he was questioned by federal agents, the news release said.

The information allegedly leaked by Ambrose includes how much Calabrese was cooperating and his travel.


While Ambrose allegedly revealed closely guarded and highly sensitive information, there was no indication that Calabrese or any other witness "was ever in danger," said Gary Shapiro, first assistant U.S. attorney. Nor is there any evidence that "any attempt was made to harm" him or anyone else, he added.

According to the FBI's complaint affidavit, Calabrese has admitted being a "made" member of the Chicago mob and has provided federal law-enforcement officials with "the most expansive overview ever of Chicago Outfit murders."

In 2002, he agreed to cooperate with the FBI investigation into mob members, including his brother Frank Calabrese Sr. and brothers James and Michael Marcello, the U.S. attorney's office said. The investigation ultimately produced indictments in April 2005 against 14 defendants, alleging a 40-year racketeering conspiracy involving 18 previously unsolved mob slayings, often of suspected government cooperators and witnesses.

Nicholas Calabrese entered the federal witness protection program in August 2002 and was placed in a federal prison.

According to the news release, Ambrose was a supervisory inspector for the marshal service's Great Lakes Regional Fugitive Task Force. On two occasions when Calabrese was brought to Chicago, Ambrose served on the night shift security detail assigned to protect him, the news release said.

In 2003, the government intercepted 11 prison conversations between the Marcellos that indicated that Michael Marcello had an inside source of information concerning Calabrese, the release stated. In one conversation, Ambrose was identified, "not by name, but by a description that could fit no other law-enforcement officer."

Michael Marcello told his brother that his source, whom he referred to as "the baby sitter," was the son of a deceased defendant prosecuted in the "Marquette 10" police corruption case in the early 1980s. Ambrose's father, Thomas, died in prison after being convicted of bribery in that investigation.

Also, Ambrose's fingerprints were found on key witness-protection documents related to Calabrese that were kept in a locked cabinet, the release said.


If convicted, Ambrose could be sentenced to 10 years in prison and fined $250,000.