Mel Gibson Focus of Domestic Inquiry

The Los Angeles Sheriff's Department is investigating Mel Gibson for a possible domestic violence incident involving his ex-girlfriend.

According to a department press release, Malibu detectives have opened a preliminary inquiry into the alleged attack, which took place Jan. 6, naming the Oscar-winning actor and director as a potential suspect and his former girlfriend, Russian singer Oksana Grigorieva, as a possible victim.

Mel Gibson's attorney, Stephen Kolodny, declined to comment, and his rep did not return phone calls immediately.

VIDEO: L.A. Sheriffs Dept. investigates Mel Gibson for possible domestic violence.Play
More Trouble for Mel Gibson

Gibson, 54, and Grigorieva, 40, are battling in court over their 8-month-old daughter, Lucia. The couple split up in April after they'd dated for more than a year. Two weeks ago, she filed for a restraining order against Gibson, claiming that he hit her at his Malibu home in January while arguing in front of their daughter. Sources close to the Russian-born singer claim that Gibson punched her in the face and broke her teeth.

According to Radaronline, Grigorieva has photos that show her bloodied and bruised after the alleged confrontation with Gibson. In published transcript excerpts from a tape recording of the incident, the website said it obtained, Radaronline claims a teary Grigorieva asked Gibson: "What kind of a man is that who would hit a woman when she is holding a child in her hands, hitting her twice in the face?"

VIDEO: Mel Gibsons ex-girlfriend says he left her a vulgar voicemail message.Play
Mel Gibson Accused of N-Word Rant

On the tape, Gibson reportedly responds: "You know what -- you f**king deserved it."

Radaronline said Gibson's lawyer emphatically denied that he was violent toward Grigorieva.

A day after Grigorieva filed for the restraining order, Gibson filed for his own restraining order. A judge upheld their recent custody agreement, which gives him overnight and unrestricted visitation rights.

"Oksana's deceitful conduct in trying to terminate Mel's access to his daughter continues," Gibson's lawyer told last week. "Making sensational allegations is not the way to resolve this."

Last week, Gibson was under fire for reportedly using a racial slur during an argument with his former girlfriend.

VIDEO: Mel Gibson files a restraining order against ex-girlfriend, Oksana Grigorieva.Play
Mel Gibson's Baby Mama Drama

Last Thursday, published transcript excerpts the site said came from an audiotape of Gibson telling his ex, Oksana Grigorieva, with whom he's battling in court over custody of their infant daughter, that the way she is dressed made her look like a "pig in heat.

"If you get raped by a pack of n***ers, it will be your fault," Gibson reportedly shouted at Grigorieva, using a deeply offensive expression for African-Americans.

Radar claims to have heard the tape, which it says Grigorieva recorded when her relationship with Gibson was unraveling. The tape reportedly also includes Gibson calling Grigorieva a whore, and other profane names offensive to women, and threatening to burn down her house.

Grigorieva's attorney Marci Levine told that it was not her client's "desire that the tape be released." She declined to comment further, citing the legal proceedings as confidential.

Gibson, however, appears to be his own worst enemy. Here's a roundup of some of his past comments that have gotten him into hot water:

Gibson's Anti-Semitic Tirade

During his July 2006 drunken driving arrest, Gibson, a traditionalist Catholic who has talked extensively about his belief in pre-Vatican II values, famously ranted, "Jews are responsible for all the wars in the world."

His anti-Semitic tirade made worldwide headlines and shocked Hollywood. Gibson later apologized for what he called "despicable behavior" and sought counseling. That October, Gibson told ABC News' Diane Sawyer that he was "ashamed" of his remarks, calling them "the stupid ramblings of a drunkard."

Gibson was sentenced to three years' probation and ordered to attend an alcohol recovery program. His criminal record was cleared in October 2009.

Gibson's Reported Remark to Female Officer

After his DUI arrest, TMZ reported that Gibson told an unidentified female sergeant, "What are you looking at, sugar t**s?"

The comment was never found in the arresting officer's report. When Sawyer read Gibson the quote during the 2006 interview, he remained silent.

But in a 2009 appearance on the "Jimmy Kimmel Show" in which Kimmel told Gibson, "In my opinion the word sugar t**s is the greatest new word in the decade," the actor said the term had been falsely attributed. Gibson added that he wished he had coined the phrase because it is funny.

Gibson's Ex-Wife Going to Hell

Though Gibson was married to ex-wife Robyn for 28 years with whom he had seven children before their breakup amid rumors of an affair with Grigorieva, he told Australia's Herald Sun in 2004 that Robyn was probably going to hell because she was not a traditionalist Catholic like him.

"There is no salvation for those outside the church," Gibson said. "I believe it. ... Put it this way: My wife is a saint. She's a much better person than I am. Honestly. She's, like, Episcopalian, Church of England. She prays, she believes in God, she knows Jesus, she believes in that stuff. And it's just not fair if she doesn't make it. She's better than I am. But that is a pronouncement from the chair. I go with it."

Gibson: Women 'Not Equal' Comment

In a 1995 Playbody interview, Gibson said he was against women priests because "men and women are just different. They're not equal."

"I have tremendous respect for women. I love them," he said. Women in my family are the center of things."

But he also called a female business partner that didn't work out a c**t and said he and feminists had a mutual dislike for each other.

"Feminists don't like me, and I don't like them," he told Playbody. "I don't get their point. I don't know why feminists have it out for me, but that's their problem, not mine."

Gibson's Anti-Gay Comments

During a 1991 interview with the Spanish newspaper El País, Gibson was asked what he thought of gay people. "They take it up the a**," he responded.

The Gay and Lesbian Alliance Against Defamation, or GLAAD, accused the star of homophobia, but Gibson later defended his comments on "Good Morning America." "If someone wants my opinion, I'll give it. What, am I supposed to lie to them?" he said.

In his 1995 Playbody interview, he said he would not apologize to GLAAD, but he did join the organization in hosting 10 lesbian and gay filmmakers on the set of "Conspiracy Theory," a 1997 film. And in 1999, when asked about the original comment, he told an interviewer he shouldn't have said it but was "tickling a bit of vodka during that interview, and the quote came back to bite me on the a**."