Bill Cosby -- LAPD Ready to Investigate Playboy Mansion Sexual Assault Claim

The LAPD is ready, willing and able to investigate sexual assault claims against Bill Cosby that allegedly occurred at the Playboy Mansion ... even though the incident is way past the statute of limitations.

As we previously reported ... a woman named Judy Huth sued Cosby Tuesday ... claiming Cosby got her drunk and then sexually assaulted her at Hefner's pad when she was 15 years old back in 1974.

Law enforcement sources tell TMZ ... the Dept.'s position is that it has "an obligation to investigate all crimes when a victim comes forward."

According to one source, it would be irresponsible to reject an investigation based on the date of the crime, because cops say there are always twists and turns and one allegation can unearth another.

Our sources say by making it known they are investigating, other alleged victims may come forward.

That said, we're told Huth has NOT filed a criminal complaint with the LAPD.