Mel Gibson and Oksana Grigorieva Mel Gibson and Oksana Grigorieva

In a sixth audio recording released by RadarOnline.com, a woman believed to be Mel Gibson's ex-girlfriend Oksana Grigorieva said Mel Gibson hit their infant daughter Lucia.

Fourth tape released: Is there any way it isn't Mel Gibson?

"You hit me, and you hit [Lucia] while she was in my hands! Mel, you're losing your mind. You need medication," Grigorieva says.

A man presumed to be Gibson replies in a rage, calling her various expletives and adding: "And I want my child, and no one will believe you!"

Fifth tape released: Is Mel Gibson broke?

Five other recordings containing threats and racial slurs have been released. Two weeks ago, Gibson was dropped by his longtime agency, William Morris Endeavor, after an audio clip believed to be Gibson criticizing Grigorieva's choice of dress first leaked.

Mel Gibson under investigation for possible domestic violence

Gibson, who's under investigation for alleged domestic violence against Grigorieva, says she threatened to leak the recordings if he didn't pay her. The actor also says she made false claims to the authorities about his alleged abuse.

Grigorieva alleged that Gibson punched her in the face multiple times on Jan. 6, breaking a tooth and causing a concussion. She filed a restraining order against him last week. The two are embroiled in a bitter custody suit for their 8-month-old daughter.