LOS ANGELES - CHRIS Brown's ad campaign with Wrigley was suspended on Monday until his criminal case is resolved, and reports surfaced that pop superstar Rihanna, his longtime girlfriend and a fellow no-show at the Grammy Awards, was the woman who accused him of assault.

The Los Angeles Times, citing law enforcement officials familiar with the case and other sources it did not name, reported that Rihanna, whose full name is Robyn Rihanna Fenty, was the woman who told police that Brown had hurt her the night before the Grammy Awards.

A police statement released on Sunday afternoon said Brown and an unidentified woman began arguing while riding in a car following a pre-Grammy party where they were spotted together on Saturday night.

The fight escalated when they got out of the car in the ritzy Hancock Park neighbourhood, the report said, and Brown was gone by the time officers arrived.

The report indicated that the woman was injured, but Brown was booked only on suspicion of making a criminal threat, a felony, after walking into a police station Sunday night. Authorities said the district attorney could choose to expand the charges.

A district attorney spokesman said police had not yet presented a case against Brown.

Brown was released after posting US$50,000 bail (S$75,000). Both he and Rihanna had backed out of their scheduled performances at the Grammy Awards, where producers scrambled to fill their slots.

Several celebrity websites such as TMZ.com, Radaronline.com, Us Weekly and People, citing sources neither named nor characterised, also reported that Rihanna was the woman involved. The Los Angeles Police Department would not confirm the reports, citing state laws that protect the identity of abuse victims.

Rihanna's publicist declined to say why the singer did not appear, and Brown's representatives also refused to discuss the allegations or his arrest. Repeated phone and email messages left beginning on Sunday night with Brown's attorney, Mark Geragos, were not returned on Monday.

Wrigley said in a statement on Monday that it was suspending its ad campaigns featuring Chris Brown as its spokesman for Doublemint gum until the situation was resolved, but stopped short of saying they will drop the troubled R&B star completely.

A company statement expresses concern about 'serious allegations made against Chris Brown,' but added that the 19-year-old should be 'afforded the same due process as any citizen.' -- AP