Backstreet Boy Nick Carter is in hot water after a woman told police she was sexually assaulted while spending the night in a house with the pop star and his assistant.

The woman told police that Carter, 26, paid for her and her female pal to travel from Wisconsin to Key West, Fl., for a vacation. On March 27, the foursome stayed at the home of a friend of the singer. According to a Key West newspaper, the woman claims she was assaulted around midnight.

Key West Police Chief Bill Mauldin said his department is investigating the woman’s claims. Carter’s attorney Jay Hershoff said: “Any allegation of sexual assault is not true. He vehemently denies this.”

Carter was arrested in 2002 after arguing with a woman in a club. In 2004, Nick’s then girlfriend Paris Hilton appeared with bruises on her face, legs and arms. Sources said they were caused by Carter. He denied the allegations.

In March 2005, he was arrested for driving under the influence and underwent an alcohol-treatment program.