Los Angeles, California (CNN) -- Audio released Friday purportedly captures an argument between Mel Gibson and ex-girlfriend Oksana Grigorieva, in which he launches into a racist, sexist rant against her.
RadarOnline released the audio, claiming the male voice is that of 54-year-old Gibson. CNN has not independently confirmed the authenticity of the tape and the voices on it.
At one point on the roughly two minute tape, the man says: "You go out in public and it's a f***ing embarrassment to me. You look like a f***ing b**** on heat and if you get raped by a pack of n***ers it will be your fault."
It's unclear when the audio was recorded.
Meanwhile, the William Morris Endeavor Publicity firm confirmed Friday that Mel Gibson is no longer their client.
Earlier this week, the Malibu Hills Police Department opened an investigation into the alleged domestic violence dispute between Gibson and Grigorieva, 40, CNN has confirmed.
Gibson has been caught in a custody dispute with Grigorieva over the couple's 8-month-old daughter. Toward the end of June, Grigorieva filed a restraining order against Gibson alleging that the actor and director struck her in the face, People magazine reported.
Police said they are still in the process of gathering information surrounding Grigorieva's allegations.
CNN reached out to both Gibson and Grigorieva's representatives for response and to verify the authenticity of the audio. Mel Gibson's longtime publicist, Alan Nierob, on Friday evening said, "We can't comment due to legal nature of the matter."
A spokesman for Grigorieva confirmed that the female voice heard on the audio tape obtained and posted by RadarOnline is the voice of Grigorieva. Stephen Jaffe also told CNN that the transcript as published on RadarOnline is an accurate transcript of a conversation she was engaged in with Gibson.
Jaffe said the site did not receive the tapes from Grigorieva. She "absolutely did not provide any tape to the media," Jaffe said.
Grigorieva has spoken with sheriff's deputies and has provided a statement to them in their domestic violence investigation, Jaffe said. The publicist said Grigorieva did not initiate the investigation.
Gibson came under fire for a racially charged tirade in 2006, when he admitted to making anti-Semitic remarks during a drunken driving arrest. He issued an apology at the time, and appealed to the Jewish community to help him recover from his alcohol addiction.