CHICAGO (CBS) — Blue Line CTA train service was halted from Wicker Park through downtown to the Near West Side Thursday evening, due to “police activity”

The Chicago Transit Authority said service on the Blue Line was suspended between the Damen stop at Milwaukee, Damen, and North avenues, and the Racine stop at Racine Avenue and the Eisenhower Expressway due to police activity at Clark-Lake.

Pink Line service was also halted between Polk Street in the Illinois Medical District and the Loop, also due to police activity at Clark-Lake.

The CTA did not specify what the police activity was.

Service was resuming on both lines by 8 p.m., but with major residual delays and congestion.

The suspension came a day after a man was shot and wounded on a Blue Line train at the UIC-Halsted stop. Patrick Waldon, 31, has been charged in that crime.

Police said around 10:45 a.m. Wednesday, Waldon shot a passenger at the busy UIC-Halsted station. Police said he staked out the platform and picked out a victim, then sat next to him.

A conversation started and the victim tried to run off the train. But he was shot in the back, and robbed of his backpack, police said. Police said multiple CTA cameras caught Waldon, and witnesses also helped nab him.