Los Angeles police have opened a criminal investigation into Smokey Robinson, after allegations of sexual assault made by four of his former housekeepers, which he denies.

The unnamed women filed a lawsuit last week alleging that the Motown star was a “a serial and sick rapist” who had assaulted them on numerous occasions between 2007 and 2024, across three residences. Robinson and his wife, Frances, are also accused of labour violations, including the failure to pay the women minimum wage and overtime. The women are seeking financial damages.

Robinson’s lawyer Christopher Frost said the allegations “defy credulity” and called them “vile, false … an ugly method of trying to extract money from an 85-year-old American icon – $50m, to be exact”.

Now, in addition to that civil lawsuit, Robinson is facing a criminal investigation.

In a statement to the press, the Los Angeles County Sheriff’s Department said it is “actively investigating criminal allegations involving William Robinson AKA ‘Smokey Robinson’. The investigation is in the early stages, and we have no further comment.”

Frost responded to the opening of the investigation, saying: “We feel confident that a determination will be made that Mr Robinson did nothing wrong, and that this is a desperate attempt to prejudice public opinion and make even more of a media circus than the plaintiffs were previously able to create.”

Robinson was one of the most successful artists to emerge from the Motown label, scoring hits under his own name and with his group the Miracles. He also wrote a number of pop classics including My Girl and Get Ready for the Temptations.

Last month he released his latest album What the World Needs Now, and he is currently touring the US, with UK dates scheduled to follow in July at Love Supreme festival plus four nationwide venues. The Guardian has contacted the festival and his UK representatives for comment.