UPDATE: Police subsequently released a person of interest in this case without charges and deemed the case “unfounded.”

CHICAGO (CBS) — A man groped a 16-year-old girl on board a CTA train Saturday morning on the Brown Line, police said.

Police said the girl was on the Brown Line platform at Belmont around 8:45 a.m., when a man approached her and asked for her phone number.

When she got on a southbound train, the man got on the same car and stared at her, then sat next to her and put his arm around her lower waist.

Police said the man held the girl against her will and touched her inappropriately before another passenger helped her get away.

The man got off the Brown Line train at Quincy.

Police described the man as an African American who is 30 to 40 years old, 5 feet 10 inches to 6 feet tall, and 170 pounds. He has a short afro, and was wearing a gray cap and black jacket with the Champion logo on the front.

Anyone with information on the incident should call Area North detectives at 312-744-8261.