University of Michigan gymnast Jacob Moore came forward this week as the first male accuser filing suit against convicted serial sexual abuser Larry Nassar, joining more than 150 other plaintiffs.

Moore, an 18-year-old freshman and a former member of the U.S. men’s junior national gymnastics team, claims in a new federal complaint that the disgraced USA Gymnastics doctor assaulted him in April 2016.

Moore, who was 16 at the time, had been seeking treatment for a shoulder injury. Nassar allegedly invited the boy to his home, and purported to treat the teen in his basement. While there, Nassar exposed Moore’s genitalia to a young female gymnast and told him that he would treat the shoulder pain “through acupuncture in his pubic area and in and around his genitalia,” the 158-page complaint claims.

Moore describes Nassar’s conduct as “sexual assault, battery, abuse, molestation, and harassment” for the former doctor’s “sexual pleasure and gratification.”

Nassar was sentenced in January to a maximum of 275 years in prison for sexually assaulting young girls. In the wake of his conviction, more than 300 girls have come forward to accuse the former Michigan State physician.

Moore’s sister, Kamerin Moore, was one of more than 150 women and girls who read victim impact statements at Nassar’s sentencing hearing in January.

“I remember how absolutely mortified I was when you asked me if I had started my period yet because you couldn’t do the treatment if I had a tampon in, and I remember becoming more uncomfortable and tense as your hand slowly massaged its way closer to my genitals,” she told Nassar.

“You abused the trust that I and so many others put in you for your own sexual gratification,” she added. “You molested a little girl who had just lost her father.”

At the hearing, Moore became emotional while describing her brother’s abuse.

“My own brother,” she said. “When he realized what a monster you are, I watched him frantically search the internet trying to find some proof that the chi in his shoulder is somehow connected to his genitals.

“My whole family was fooled by you, but I know now who you really are—a child molester and a master manipulator,” she added.

USA Gymnastics claims that it reported Nassar to the FBI in July 2015, according to International Gymnast magazine, which first reported Moore’s complaint late Thursday. He was suspended by Michigan State University in August 2016, after Rachael Denhollander told police that Nassar had sexually assaulted her in 2000.

Moore’s complaint is part of the federal lawsuit initially filed by Denhollander, the first person to publicly accuse Nassar of sexual abuse. Denhollander’s suit names Nassar, USA Gymnastics, and Michigan State University as defendants.

Nassar is currently in a maximum-security federal prison in Tucson, according to International Gymnast.