Demetrius Warren, of the 5800 block of South Michigan Avenue, became the fourth person Monday charged with first-degree murder in connection with the death of graduate student Amadou Cisse, according to the Chicago Police Department.

Warren had previously been charged with two counts of armed robbery in connection with a series of incidents near campus November. In addition to the murder charge, he was charged Monday with an additional count of attempted robbery.

Also charged with murder in the case are Jamal Bracey, 17, of the 6100 block of South Damen Avenue, Eric Walker, 16, Chicago, and Benjamin Williams, 21, of south suburban Dolton.