Authorities have released a sketch of a suspect in a sexual assault and armed robbery last week in southwest suburban Palos Hills.

The robbery and assault occurred Sept. 9 near 99th Street and 84th Avenue, according to a statement from Palos Hills police. Police are offering a $1,000 reward for information leading to the arrest and conviction of the person responsible.

The suspect is described as a 5-foot-6 to 5-foot-7 black male between 17 and 19 years old, police said. He weighs 120-127 pounds and has large round eyes, a wide nose and a light-colored blemish above his left cheekbone.

Anyone with information about the incident or the suspect should call the Palos Hills Police Department at (708) 598-2992 or submit an anonymous tip to (708) 598-2659.