TORONTO -- A 67-year-old man is accused of sexually assaulting homeless woman while working at an Oshawa, Ont., outreach centre, Durham Regional Police said Wednesday.

A number of women recently came forward with the accusations against the Scugog, Ont., man, some of which date back 15 years, police said.

Earl Sanderson is charged with four counts of sexual assault.

The accused was a volunteer and a staff member at Gate 3:16, on Simcoe St. S., between 1995 and 2012, police said, adding his roles at the drop-in centre for homeless people included teaching and counselling.

Police have not released any details of the alleged assaults but they said investigators are concerned about the possibility of other victims.

Anyone with any information regarding this historical sex assault case is asked to contact the lead investigator Det. Kim Bagg at 1-888-579-1520, ext. 5340.