Pedro Villareal, 34, is accused of fatally shooting one man and injuring another after a struggle aboard a Pink Line CTA train in the Loop in December, police said.

A 37-year-old man was pronounced dead after being found unresponsive and stabbed overnight on CTA property in the Loop, Chicago police said.

Pedro Villarreal faces murder charges for a fatal shooting on CTA's Pink Line last month in the Loop, where he allegedly shot two men, killing one, during a dispute. He was also charged with trespassing and claims self-defense.

A police investigation is underway at the CTA Blue Line station in The Loop on Friday afternoon. A large emergency response was seen above the Washington CTA station on Dearborn Street just before 12:30 a.m. CBS News Chicago has reached out to the Chicago Police Department for more information.

Chicago police are investigating a string of stabbings on CTA property after a man was seriously wounded early Sunday on the Red Line, marking the fourth such attack in five days.

The 120-year-old station is one of the CTA’s most heavily used and serves the Purple, Pink, Brown, Orange and Pink Lines.

Heads up riders! The CTA said no trains will run on the Loop elevated rails this weekend. The CTA is urging riders this weekend to plan for extra travel time, even outside the Loop, and because of other infrastructure projects, driving downtown may not be ...