"Extortion allegations have been brought to our attention and we are certainly going to be looking at that," Sheriff Department spokesman Steve Whitmore told TMZ on Wednesday. He did not elaborate.
Whitmore said last week that detectives looking into allegations that Gibson harmed Grigorieva in a January incident had received audio recordings from the pair’s closed child custody case over their 8-month-old daughter Lucia. Cops were working to authenticate the tapes, Whitmore said.
It is unclear whether the tapes in either investigation include those that have been posted on a near daily basis for more than weeks by the celebrity website RadarOnline -- recordings that, while unverified, have left Gibson’s reputation in tatters.
On clips from the profanity-laced tapes, a man who sounds like Gibson is heard berating a woman said to be Grigorieva in several arguments. Radar released a sixth tape Tuesday that purportedly documented Gibson telling Grigorieva "no one would believe" her claim that he hit her and Lucia.
Earlier this month, cops interviewed Grigorieva in connection with their domestic violence probe.
A spokesman for the Russian pop singer declined to comment to The Associated Press Wednesday on the latest developments.
Back in 2006, Gibson’s career was nearly derailed when he went on an anti-Semitic and sexist rant against the officer who arrested him for driving under the influence.
Since Radar's recordings hit the web, the "Braveheart" star has been dropped by his longtime talent agency and become a late-night punch line.
California Gov. Arnold Schwarzenegger reportedly made a few Gibson jabs of his own during daylight hours on Wednesday.
Speaking to a group of utility commissioners in Sacramento, Schwarzenegger cited BP's progress on its leaking well in the Gulf of Mexico but said, "no one has figured out how to contain Mel Gibson," The Associated Press reported.
Schwarzenegger also told the crowd to turn off their cell phones because "because we are expecting a call from him."
When asked for comment, Gibson's rep told the AP the "Terminator" star was "obviously paving the way for a return to showbiz."