LOS ANGELES•Detectives from the Los Angeles Police Department's "threat management" squad have opened a criminal investigation of actor Charlie Sheen, a police spokesman said on Wednesday.
The police disclosed little else about the investigation, which the spokesman said began with a complaint lodged against the actor on March 31.
The spokesman declined to provide any information about the nature of the alleged victim or threat, but said investigators had obtained a search warrant in the case.
Unconfirmed reports from media outlets, including Variety magazine and RadarOnline.com, referred to an audio tape they said was at the centre of the investigation.
Variety said that in an "alleged audiotape", Sheen was apparently heard threatening to hire a hitman for US$20,000 (S$27,130) to kill his ex-fiancee Scottine Ross.
He also allegedly admitted in the tape to having lied to a sex partner about his HIV status, Variety said.
The alleged recording obtained by the police was reportedly made by a former lover who confronted Sheen after he revealed his HIV status on national television in November.
A lawyer for Sheen, best known for his starring role on the longrunning CBS hit comedy Two And A Half Men, could not be reached for comment.
The police investigation marks the latest brush with the law for the 50-year-old actor, whose career has been overshadowed for years by his admittedly raucous lifestyle, substance abuse and legal troubles.
REUTERS, AGENCE FRANCE-PRESSE