York Regional Police are canvassing for evidence in a Markham neighbourhood after an unknown suspect forcefully dragged a woman between two houses on Wednesday night.

The incident happened sometime between 8 p.m. and 8:30 p.m. in an alleyway just off Woodhall Road, which is north of Steeles Avenue East and west of McCowan Road.

According to investigators with the York Regional Police Special Victims Unit – Sexual Assault Section, a woman was walking through an alleyway from McCowan Road to Woodhall Road when an unknown man grabbed her and " forcefully dragged her between two houses.”

“Officers learned that motion-sensor lights went off between the two homes and a person was walking a dog in the area, which may have scared the suspect away,” police said in a news release.

He is described as a male and standing five foot 10 with a medium build. He was last seen wearing dark clothing.

York police say that investigators want to speak with one potential witness who was seen walking a dog near the alley and Woodhall Road at the time.

They also want to talk to anyone who may have witnessed the incident or anyone who may have dash cam or video surveillance footage that could help with their investigation.