Los Angeles (CNN) -- Allegations that Mel Gibson's ex-girlfriend tried to extort millions from the actor during their child custody battle are being reviewed by prosecutors, a spokeswoman for the Los Angeles County district attorney said Wednesday.

The same prosecutors are also considering domestic violence allegations against Gibson stemming from an incident a year ago with Oksana Grigorieva, the mother of Gibson's 3-year-old daughter.

The former couple are in a bitter legal fight over custody of the child.

Detectives have been investigating Gibson's charge that Grigorieva, a Russian musician, tried to extort him with recordings she made of his telephone calls, a Los Angeles County Sheriff's spokesman said.

The case against Grigorieva was presented to prosecutors Wednesday, according to spokeswoman Sandi Gibbons.

While Los Angeles County Sheriff's investigators handed over their evidence against Gibson in August, prosecutors have been waiting for the completion of the extortion probe before making decisions on either case, the district attorney's office said earlier.

There was no indication of how long the review will last before a decision on charges is announced.