A 60-year-old Toronto man faces multiple charges of drugging and sexually assaulting several women, many of them sex workers.

York Regional Police allege the suspect located his victims through a number of websites and arranged meetings with them in Toronto, Markham, Belleville, Cobourg and Oshawa.

Police say the women were drugged, rendering them unconscious, and then sexually assaulted.

Investigators allege the suspect photographed and videotaped the victims as he assaulted them.

To date, none of the victims contacted by police had any recollection of being videotaped or photographed.

“Most of them were stunned, they were completely unaware of what had transpired,” Det.-Sgt. Randy Slade told CTV Toronto. “There seems to be a blank in their memory, which is consistent with what was shown on the video.”

Police are encouraging any other victims to come forward and contact them.

Allen Chow, of Toronto, faces 21 counts of sexual assault. He was arrested Monday without incident, police said.

None of the allegations against him have been proven in court.

Information about this case can be reported anonymously through Crime Stoppers at 1-800-222-TIPS.

With a report from CTV Toronto’s Tamara Cherry