Evanston police released a surveillance video Thursday taken across the street from an alleged sexual assault and robbery near the Chicago-Evanston border.

Authorities say they are still searching for the man who sexually assaulted and robbed a 19-year-old woman Tuesday morning in the 1700 block of Howard Street.

The surveillance video, captured at about 6 a.m. Tuesday, shows the man forcing the woman into an alley on the Evanston side of the street. About 40 seconds after the man and woman disappear from the view of the surveillance camera, the woman emerges from a gangway and flees west along the Evanston side of the street.

The man dragged the woman into the gangway of a vacant building and sexually assaulted her before she broke free and alerted authorities, police said. She later realized her purse was missing.

Police described the man as black, 30 years old, having a dark complexion and thin build, and wearing a blue baseball cap and black T-shirt. Authorities are encouraging any drivers or pedestrians who may have witnessed the incident to come forward.

— Ciara McCarthy