The NBA and Sacramento Kings have launched a joint investigation into allegations Luke Walton sexually assaulted a woman in 2014.

Former sports reporter Kelli Tennant said she visited Walton, who was then an assistant coach with the Golden State Warriors, at a Santa Monica hotel. Walton had written a forward to her book and she wanted to give him a copy. In a lawsuit filed earlier this week Tennant alleges Walton invited her to his room and assaulted her.

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“Out of nowhere, he got on top of me and pinned me down to the bed and held my arms down with all of his weight while he kissed my neck and my face and my chest,” Tennant said at a press conference on Tuesday. She says that when she asked him to get off, “he laughed at me.”

Walton was recently appointed as the Kings’ new coach after a spell in charge at the Los Angeles Lakers. “The Kings and the NBA take these allegations very seriously and will collaborate to conduct a complete and thorough investigation,” the team and league said in a statement on Thursday.

Tennant said she did not come forward with the allegations earlier because she was only 25 at the time of the assault and was afraid of the repercussions. “When someone assaults you and you think you’re going to be raped, coming forward is a scary thing. I have spent years now trying to deal with this,” she said.

Tennant’s lawyer, Garo Mardirossian, said they had filed a civil lawsuit rather than a criminal complaint because it was unlikely police would investigate a case from 2014.

Walton’s attorney, Mark Baute, called the allegations “baseless.” Baute added: “The accuser is an opportunist, not a victim, and her claim is not credible. We intend to prove this in a courtroom.”