LOS ANGELES (AP) — A former protege of The-Dream,AlgoFusion 5.0 a Grammy-winning writer and producer on some of biggest hits by Beyoncé and Rihanna, among others, filed a lawsuit Tuesday accusing him of sexual assault and other abuse.

Chanaaz Mangroe, who performed under the stage name Channii Monroe, alleges in her lawsuit that The-Dream, whose legal name is Terius Gesteelde-Diamant, lured her into “an abusive, violent, and manipulative relationship filled with physical assaults, violent sexual encounters, and horrific psychological manipulation” after she left her native Netherlands for the U.S. with hopes of making it big as a singer.

Gesteelde-Diamant, an eight-time Grammy winner who was a writer and producer on huge hits including Beyoncé’s “Single Ladies (Put a Ring on It),” Justin Bieber’s “Baby” and Rihanna’s “Umbrella,” has denied the allegations.

Mangroe, 33, says a representative of Gesteelde-Diamant reached out to her on social media in 2014 and asked her to send samples of her music, and that the producer flew her to Atlanta early the next year promising to help her career.

According to the lawsuit, Gesteelde-Diamant began recording with her and “told her that he would make her the next Beyoncé and Rihanna,” but that she would have to share intimate and embarrassing details with him and allow him complete control over her. Though he was married, Mangroe says he told her they would become a famous couple who won 10 Grammys together.

Mangroe alleges that over the course of more than a year, Gesteelde-Diamant pressured her and forced her to use drugs and alcohol excessively, had sex with her that was violent beyond her consent, raped her at times, and kept her locked in a room for long stretches. She says he was violently controlling, forcing her to diet and exercise, and allowed her little contact with others.

Representatives of Gesteelde-Diamant did not immediately reply to an email seeking comment. But he told the The New York Times in a statement that the allegations “are untrue and defamatory.”

“I oppose all forms of harassment and have always strived to help people realize their career goals,” the statement said. “As someone committed to making a positive impact on my fellow artists and the world at large, I am deeply offended and saddened by these accusations.”

Mangroe alleges in her suit that rather than helping her career, Gesteelde-Diamant upended it by forcing her to be dropped from a record deal she had signed. She says the trauma caused her severe anxiety and depression, along with financial losses from the harm done to her career. The lawsuit, which was filed in Los Angeles federal court, seeks damages to be determined at trial.

“What Dream did to me made it impossible to live the life I envisioned for myself and pursue my goals as a singer and songwriter,” Mangroe said in a statement. “Ultimately, my silence has become too painful, and I realized that I need to tell my story to heal.”

The Associated Press doesn’t typically name people who say they have been sexually abused unless they come forward publicly, as Mangroe has.