A former counselor at a Chicago behavioral health center was charged with sexually abusing five young patients in the late 1990s and early 2000s, prosecutors said.

Edmund Rivers, 68, was previously employed as a mental health counselor at Hartgrove Behavioral Health Hospital, which is currently known as Hartgrove Behavioral Health System. He was charged with three counts of criminal sexual assault and two counts of predatory criminal sexual assault in connection with alleged crimes involving 7-to-14-year-old boys between 1996 and 2004, the Cook County State’s Attorney’s Office said.

According to prosecutors, Rivers abused minor patients in several locations at the facility, including patient rooms, a “seclusion” room, a cafeteria bathroom and a gym equipment room. The five victims, who didn’t know each other, said Rivers would allegedly threaten to sedate them with a hypodermic needle for failing to comply with his advances, the state’s attorneys’ office said.

A number of the victims came forward to law enforcement after hearing about a civil lawsuit that was filed against the behavioral health facility, alleging a pattern of staff abuse.

A hearing took place for Rivers on Monday at the Leighton Criminal Court Building, and a judge ordered he be detained.

“This alleged abuse is horrific, and the survivors have shown tremendous courage coming forward to report these allegations after so many years,” Cook County State’s Attorney Eileen O’Neill Burke said in a news release. “Instead of receiving support during a vulnerable time in their youth, these victims were allegedly violated by someone in a position of trust and authority…”