CHICAGO (CBS) — An 18-year-old man has been charged with killing former U.S. Marine Mamadou Balde earlier this week, by pushing him in front of a moving CTA train downtown.

Balde, 29, died at the Jackson Red Line stop on Tuesday, after he tried to walk away from a fight on the platform. Police said Balde was on the platform around 5:15 p.m., when 18-year-old Ryan Munn and two other assailants came up to him.

READ MORE: Ed’s Driveway: Toyota Sienna

Mamadou Balde (Photo supplied to CBS)

Police said Munn punched Balde, and pushed him in front of a train.

READ MORE: Boy Shot, Killed In Gresham Neighborhood

Munn was arrested Friday night after detectives identified him as Balde’s killer, police said. He has been charged with one count of first-degree murder.

Munn is expected to appear for a bond hearing Sunday afternoon.

Ryann Munn is charged with first-degree murder in the death of former U.S. Marine Mamadou Balde, who was pushed in front of a moving CTA train on April 7, 2020. (Source: Chicago Police)

MORE NEWS: Chicago Weather: Frost Advisory, Sunny Through The Day