Police in the US have begun an investigation into claims the comedian Bill Cosby molested a woman when she was 15 years old.

The investigation was opened after Judy Huth, who is suing Mr Cosby for sexual battery, met Los Angeles police detectives for 90 minutes.

LAPD officer Jane Kim confirmed the department had opened its investigation after the meeting.

Ms Huth's civil suit claims Mr Cosby forced her to perform a sex act on him in a bedroom of the Playboy Mansion in LA in 1974.

His lawyers have dismissed the claim as "patently false".

Celebrity women's rights lawyer Gloria Allred said Ms Huth met two special victim unit detectives on Friday, three days after her lawsuit was filed.

"We are going to provide any and all evidence that she has," Ms Allred said.

Police did not give any additional details about the investigation.

Mr Cosby's lawyer, Martin Singer, has accused Ms Huth and another lawyer of extortion and said she attempted to sell her story to a tabloid newspaper a decade earlier.

Mr Singer's filing states the other lawyer, Marc Strecker, first demanded US$100,000 for Ms Huth to remain silent, then raised the demand to US$250,000 as more women came forward accusing Mr Cosby of sexual misconduct.

Walk of Fame star vandalised

Mr Cosby (77) has been accused by more than 15 women in recent weeks of sexual misconduct, ranging from incidents of groping to incidents of drugging and raping.

He has never been charged with a crime, and his lawyers have denied many of the allegations, calling them discredited and defamatory.

On Thursday, Los Angeles police chief Charlie Beck said the force would be willing to investigate sexual abuse allegations against him if someone files a complaint.

He said: "We don't turn people away because things are out of statute. You come to us, especially with a sexual allegation, and we will work with you."

"The remedies may be limited but it's important to recognise that in many cases going through the process for a victim is very therapeutic so we address these things seriously and it's not just because it's Mr Cosby."

Mr Cosby has yet to respond himself to the allegations, but has cancelled a number of public appearances in recent weeks.

Meanwhile, vandals have daubed the word "rapist" on the star dedicated to Cosby on Hollywood's Walk of Fame.

Police confirmed they are investigating after the word was written several times on the tribute to the comic on Hollywood Boulevard. Crews have since removed the words from the pavement.

The Hollywood Chamber of Commerce issued a statement saying: "The Hollywood Walk of Fame is an institution celebrating the positive contributions of the inductees."

"When people are unhappy with one of our honorees, we would hope that they would project their anger in more positive ways than to vandalise a California state landmark."