Los Angeles - The Los Angeles County District Attorney’s Office said the 2015 sexual assault allegations against Morton legend Smoky Robinson were reported, but no charges were filed due to insufficient evidence.

The Los Angeles County Sheriff’s Department filed a decade-long charge with the prosecutor’s office that had nothing to do with the recent civil lawsuit that accused Robinson of sexual assault, the attorney said on the issue.

Robinson, 85, has not been charged with any crime and has denied any misconduct. Celebrity news site TMZ first reported a 2015 investigation on Friday.

"We found out that our office filed sexual assault charges against Mr. Robinson in 2015 by the Los Angeles County Sheriff's Department," the District Attorney's Office said in a statement Friday.

“For that matter, evidence based on this is not enough to reject the charges,” the District Attorney’s Office said. “We are currently unable to provide more information due to ongoing law enforcement investigations.”

The Los Angeles County Sheriff’s Department confirmed that it conducted an investigation and made no charges.

"We cannot provide more information due to the confidential nature of the investigation," the Sheriff's Department said in a statement Friday.

Earlier this month, Robinson was sued by four former housekeepers for sexual assault by the singer who "you really have control over me." The lawsuit costs at least $50 million, and also named Robinson's wife and accused her of knowing the allegations.

Robinson denied the request, refuting the four women and their attorneys this week, accusing them of defamation and seeking at least $500 million.

Christopher Frost, the attorney representing Robinson and his wife, said his client insisted on his innocence.

"One unfortunate aspect of celebrities is that it is not uncommon to be targeted with false and unproven charges," Frost said. "Mr. Robinson looks forward to the conclusions of the current investigation and there is no doubt that a similar decision will be reached here."

Lawyers prosecuting Robinson women said Friday that the rejection of criminal cases in 2015 only means a lack of evidence.

According to attorneys John Harris and Herbert Hayden, the person who filed the charges in 2015 was not anyone of the four women who sued Robinson.

"The statement issued by the Los Angeles County District Attorney's Office confirmed that there was no lawsuit against Mr. Robinson due to insufficient evidence, and it was not because the claim lacked merits."

“This highlights the significant challenges facing victims when reporting sexual assaults, especially when the so-called perpetrator is a powerful and well-known figure,” they said.

NBC News reported on May 15 that Robinson is under criminal investigation, citing law enforcement sources who did not name it.

Robinson is an iconic American soul singer who has had a career of more than 70 years.

The recording, production and songwriting legend was a pioneer of Motown Records, founded the vocal group The Miracles in the 1950s, and later released albums as a solo artist and served as record director for the record company. In 1987, he was inducted into the Rock and Roll Hall of Fame.