A doctor who police say has spent two decades providing medical assistance to youth hockey teams in Michigan and Minnesota has been charged after patients in the Detroit area accused him of sexual assault.

Zvi Levran was arraigned Friday in 47th District Court on multiple criminal sexual conduct charges involving several patients, according to police in Farmington Hills, Michigan. Levran’s attorney entered a not-guilty plea on his behalf.

The patients told police that their examinations were in some way connected to youth hockey organizations. Police have released no information about the ages or genders of Levran’s accusers, nor when the alleged assaults took place.

Levran was ordered held on a $1 million bond. He also was ordered to surrender his passports, treat no patients at his home and have no unsupervised contact with patients.

A pre-exam conference has been scheduled for Dec. 7.

His attorney, Joseph Lavigne, told The Associated Press Friday that he has no information yet on what has been alleged, but that Levran intends to defend himself against the charges.

Levran also was charged last month after a 19-year-old man told authorities he was sexually assaulted during an Oct. 18 examination in Levran’s home office, northwest of Detroit.

n that case, Levran was arraigned in October on seven criminal sexual conduct charges, ordered not to leave Michigan and told to have no contact with minors or hockey players.

Investigators say they are concerned there could be other victims who have not yet come forward.

The role of sports doctors and their interactions with athletes have come under scrutiny in recent years.

Former Michigan State University sports doctor Larry Nassar was sentenced in 2018 to 40 to 175 years in prison after admitting to molesting some of the nation’s top gymnasts for years under the guise of medical treatment. He was accused of sexually assaulting hundreds of women and girls.

Former University of Michigan athletes, students and others have said they were molested by University of Michigan sports doctor Robert Anderson. Anderson was director of the campus health service and a physician for multiple sports teams, including football. He died in 2008 after working at the university for nearly 40 years.