Photo: Jon Cryer, left, Charlie Sheen and Angus T. Jones appear in "Two and a Half Men."
In December, Sheen spent part of Christmas in jail after being arrested in Aspen for allegedly threatening to kill his wife, Brooke Mueller, with a knife.
Now, Cryer has told authorities that his ex-wife, Sarah Trigger, has hired a hit man to kill him.
The FBI has been on the case for a week, sources told celebrity Website TMZ.
Photo: Actor Charlie Sheen and Brooke Mueller.
Cryer and Trigger went through what has been described as a very bitter divorce and are involved in a custody fight.
Security descended on the set of "Two and a Half Men" last Friday after the threats, TMZ reports, and the show was taped without an audience.
Vicki Greene, a lawyer for Trigger, denies that her client had any involvement. "There's no reason in the world why Sarah would do anything like that," Greene said.
Photo: Jon Cryer kisses his 2009 Emmy award for best supporting actor.
Trigger was arrested last year for felony child neglect.
PICTURES: Charlie Sheen
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