CHICAGO (CBS) — Chicago police said detectives were questioning a person of interest Tuesday morning in the groping of a young woman on board a CTA Red Line train last week.

During the morning rush last Wednesday, a 23-year-old woman was riding a Red Line train headed downtown between the North/Clybourn and Chicago stops, when a man made “inappropriate contact.”

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The man got off the train at Chicago Avenue and disappeared, but police circulated several images of the man from surveillance cameras on the train and platforms.

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Sources said the man also left DNA evidence.

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Detectives were questioning a person of interest Tuesday morning for a case they’re calling criminal sexual abuse.