It happened Friday morning as the 16-year-old was walking in the 8100-block of South Crandon. She was able to get away safely.
Police say the man they are looking for is 25-to-27 years old. They have released a sketch of the offender. He is described as African-American, 6-feet 8-inches tall, weighing 180-to-200 pounds, with brown eyes and a light complexion.
Anyone with information should call Chicago Police.