Liziane Gutierrez has accused Brown of attacking her, and police officials in Sin City are investigating her claims, but the Kiss Kiss star's aides insist the cops are wasting their time.

They allege Gutierrez is simply upset she got kicked out of Brown's private party at The Palms early on Saturday (02Jan15) for being disruptive.

But she maintains Brown flew into a rage after she sneaked her cellphone past security and into his suite, and took a photograph of the host, who then confronted the Brazilian model and punched her in the left eye.

A rep tells Liziane never had the phone inside the party and her story about Chris becoming enraged when she tried to take a snap is a complete lie.

The accuser isn't new to celebrity feuds - she fell out with Jason Derulo in August (15).

According to, she fired off at the singer, claiming he left her stranded at The Argyle hotel in Hollywood after flying her to Los Angeles from Las Vegas.

Sources close to Derulo told the website he had no idea who she was.