Mel Gibson Focus of Domestic Violence Inquiry

LOS ANGELES (CBS/AP) Updated 4:10 p.m. EST

Mel Gibson is being investigated in a possible domestic violence incident involving his ex-girlfriend earlier this year, sheriff's officials said Thursday.

The Los Angeles County Sheriff's Department listed the actor-director as a potential suspect in the alleged attack on his ex-girlfriend, Russian singer Oksana Grigorieva, at an undisclosed location in Malibu.

Sheriff's spokesman Steve Whitmore said detectives interviewed Grigorieva on Monday. She has been the only person interviewed so far.

Whitmore declined to disclose further details of the investigation or any potential evidence.
   
"We're in the process of verifying, verifying, verifying," Whitmore said. "All the allegations that have been put forth will be thoroughly investigated."

A news release from the agency states the incident occurred Jan. 6 and the investigation is in a preliminary stage.

A phone message left for Alan Nierob, Gibson's spokesman, was not immediately returned.

It was reported last week that the actor was allegedly caught on tape using a string of racist and derogatory remarks in a profanity-laced argument with Grigorieva.

The two are currently in the midst of a custody battle over their 8-month-old daughter, Lucia.

In 2006, Gibson unleashed a now-infamous anti-Semitic tirade to police following a drunk driving arrest. He later apologized for his "despicable" comments and "out of control" behavior.

Gibson is no longer on probation for that case and his conviction has since been expunged.

The actor has not publicly discussed the breakup with Grigorieva, 40. The former couple first revealed their relationship shortly after Gibson's wife, Robyn, filed for divorce last April.
   
Whitmore said it may take a month to conclude the investigation. The results will then be turned over to the district attorney's office, which will decide whether to pursue charges.