The Los Angeles Police Department said on Thursday that it had opened an investigation into a woman’s allegation that she had been sexually assaulted by the actor Armie Hammer, whose Hollywood career has recently been derailed by allegations that he physically abused women.
The department said that it had been contacted on Feb. 3 by a lawyer representing “a female community member.” After speaking with the woman, the department said, it began an investigation into Mr. Hammer by the Special Assault Section.
“There is an open investigation in which he is a named suspect in an alleged sexual assault,” Officer Norma Eisenman, a Los Angeles police spokeswoman, said. She declined to discuss the case in further detail.
The department disclosed the investigation after a woman said at an online news conference on Thursday that Mr. Hammer had raped her for more than four hours in Los Angeles on April 24, 2017. She said Mr. Hammer had repeatedly slammed her head against a wall, bruising her face, and had beaten her feet with a crop.
“During those four hours, I tried to get away, but he wouldn’t let me,” the woman, who is 24 and lives in Europe, said through tears at the news conference, which was organized by the lawyer Gloria Allred. “I thought that he was going to kill me. He then left with no concern for my well-being. I was completely in shock and I couldn’t believe that someone I loved did that to me.”
Mr. Hammer’s lawyer, Andrew B. Brettler, said that the woman’s “own correspondence with Mr. Hammer undermines and refutes her outrageous allegations.”
“From Day 1, Mr. Hammer has maintained that all of his interactions” with the woman and with every other sexual partner “have been completely consensual, discussed and agreed upon in advance, and mutually participatory,” Mr. Brettler said.
Mr. Hammer gained fame as an actor in films such as “The Social Network,” in 2010, in which he played both Cameron and Tyler Winklevoss, twin brothers who accused the Facebook founder Mark Zuckerberg of stealing their idea.
In 2017, Mr. Hammer starred in the dramatic film “Call Me by Your Name,” for which he received a Golden Globe nomination for best supporting actor, and voiced a character in the third installment of the “Cars” movie franchise.
In July 2020, Mr. Hammer’s wife of 10 years, Elizabeth Chambers, a television personality, filed for divorce, and Mr. Hammer’s career seemed to implode amid allegations by two women that he had physically abused them.
In early January, an anonymous account on Instagram published private messages purportedly written by Mr. Hammer, in which he said, among other things, “I need to drink your blood,” and “I am a 100% cannibal.” The comments circulated widely on social media.
A lawyer for Mr. Hammer on Thursday night referred to an earlier statement he had made denying allegations that he had physically abused a former girlfriend.
“These assertions about Mr. Hammer are patently untrue,” the lawyer said in a statement issued in January to US magazine. “Any interactions with this person, or any partner of his, were completely consensual in that they were fully discussed, agreed upon, and mutually participatory.”
At the news conference with Ms. Allred, the woman said she had met Mr. Hammer on Facebook in 2016 and their relationship had “progressed rapidly and the emotions from both sides became really intense.”
“He would often test my devotion to him, slyly removing and crossing my boundaries, as he became increasingly more violent,” she said. “He abused me mentally, emotionally, and sexually.”