ST. LOUIS – A teenager is behind bars in the shooting death of another teenager who was killed Monday in St. Louis while he was playing video games.

Prosecutors have charged Marshean Barnett, 19, with first-degree murder and armed criminal action in the case. Barnett is accused in the shooting death of Derrick Johnson, 19, of University City.

The shooting happened around 4 p.m. Monday in the 4900 block of Leahy Avenue in the Mark Twain neighborhood. Investigators say Johnson was playing video games in the home with someone when someone unknown to him entered the home and shot him.

Police have not yet disclosed any potential motives. The St. Louis Metropolitan Police Department is investigating the case.