It happened during the evening rush hour, about 5:35 p.m., on Aug. 29th at the 95th Street Red Line Station.
Police said the suspects robbed two people and injured a third.
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A pair of headphones and a cell phone were taken, and the third person suffered a fracture.
The individuals can be seen wearing a black Nike jacket, black shirt and blue jeans, blue jacket, and red shirt and a backpack.
Anyone with information is asked to contact the Bureau of Detectives/Mass Transit at 312-745-4443.