Charlie Sheen is being investigated by detectives from an elite anti-stalking unit, police have said.
The 50-year-old actor has been listed as a suspect in a criminal investigation report received on March 31, LAPD officer Matthew Ludwig revealed.
US media reported that police were investigating a 35-minute audio recording purportedly of Sheen threatening his ex-fiancee, Scottine Ross.
She performed in porn films under the name Brett Rossi and is suing Sheen for having sex with her without disclosing he is HIV positive.
Her lawsuit states she and Sheen had sex five times before the actor told her about his condition, and that the actor repeatedly threatened to kill her during their relationship, which ended in 2014.
She also accused Sheen of physical abuse, including kicking her on the ground during one incident.
The Two and a Half Men star publicly revealed he was HIV positive on the US Today show in November, but said he had disclosed his status to all his sexual partners.
He also vowed during the appearance that he would not pay to settle any claims from sexual partners claiming he exposed them to the virus that causes Aids.
There was no immediate comment available from Sheen's lawyer or publicist.