They just signed his death warrant.

(WSJ) — U.S. officials Monday acknowledged for the first time that former Special Forces soldier Raymond Davis, held in detention in Pakistan for killing two armed men, works for the Central Intelligence Agency, but said he was not directly involved in spying operations.

U.S.officials say Mr. Davis, who has been held in the eastern city of Lahore since late January, was on a short-term contract as a protective officer, responsible for providing security to officials with the CIA and other agencies in the country.

“Rumors to the contrary are simply wrong,” a U.S. official said of Pakistani claims that Mr. Davis was directly involved in intelligence gathering operations.  The U.S. says Mr. Davis, 36 years, shot the two men in self-defense when they tried to rob him.

President Barack Obama, referring to Mr. Davis as “our diplomat”, said last week that he was covered by diplomatic immunity and should be immediately released. Facing public anger over the killings, Pakistan has refused to do so.

The Davis case has deeply strained relations between U.S. and Pakistani spy agencies, threatening counterterrorism cooperation against militants in tribal areas bordering Afghanistan, officials say. U.S.officials say Washington fears for Mr. Davis’s life, and they have appealed to the Pakistanis to do more to ensure his security.

The jail where Mr. Davis is being held holds about 4,000 inmates, most of them militants, according to U.S. officials.

Mr. Davis has been moved to a separate part of the facility. U.S. officials say all the guards have had their guns taken away for fear that one of them may kill him, and dogs are tasting or smelling his food to make sure it doesn’t contain poison.