US prosecutors will not press charges against veteran comedian Bill Cosby over allegations he sexually assaulted a 15-year-old girl at the Playboy mansion in 1974.

The Los Angeles County prosecutor’s office cited the statute of limitations – which limits how long legal action can be taken after an alleged crime – in declining to pursue the case, brought by Judy Huth earlier this month.

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About 20 women have accused the 77-year-old Emmy and Golden Globe winner of sexual assault and even rape in alleged incidents dating mostly from decades ago.

But so far the only one who had taken legal action was Huth, who was represented by celebrity lawyer Gloria Allred.

“Given that 40 years have passed since the alleged incident, prosecution (on a misdemeanour count) … is declined due to the expiration of the statute of limitations,” wrote Deputy District Attorney Victor Rodriguez.

“Even if there was an applicable … charge, the statute of limitations that existed in 1974 for felony sex crimes was three years.

“Therefore prosecution today for any potential felony sex crime from 1974 would also be barred.”

Allred did not immediately respond to a request for reaction to the prosecutor’s decision.

Cosby is famous for his role in The Cosby Show, a popular family sitcom that aired in the 1980s and 1990s.