CHICAGO (CBS) — A jury has found a man guilty in the murder of University of Chicago graduate student Amadou Cisse, who was gunned down just blocks from campus four years ago.

Demetrius Warren, 21, was convicted Monday of first-degree murder in the Nov. 18, 2007, slaying.

READ MORE: 1 Person Dead, Another Injured In 4 Car Crash In Waukegan

Another defendant, Jamal Bracey, pleaded guilty and was sentenced to 35 years in prison for his role in the murder last year. A third, Benjamin Williams, was sentenced to 41 years after a guilty plea.

A fourth, Eric Walker, agreed to testify for the prosecution against Warren in exchange for 20 years in prison, the Chicago Sun-Times reported.

Prosecutors said Bracey and Warren stole two guns — a .22 caliber and .38 caliber — from a home in the 7000 block of South Euclid Avenue on Nov. 13, 2007.

Warren shot Cisse, 29, once in the chest with the stolen .22 as he and Williams tried to grab Cisse’s book bag in the 6100 block of South Ellis Avenue, Cook County State’s Attorney Andreana Turano charged in court during Williams’ sentencing hearing in December of last year.

Cisse, a Senegalese national who was a month away from earning his Ph.D. in chemistry, had attended an ice cream social and chatted with friends the night he was killed. He had just left campus with his backpack and a water bottle when he was accosted about 1:30 a.m., Turano said.

READ MORE: Woman, 2 Children In Hospital After Building Fire In Homan Square

The site where Cisse was shot is only about a block from the Burton-Judson undergraduate dormitory, and the South Campus Residence Hall, which opened about two years after Cisse’s murder.

Bracey was in a Pontiac Bonneville with the driver, Eric Walker, and another person, waiting as the shooting took place, she said.

All five had been driving around in the car as Warren went on a spree, holding up others, sometimes with the assistance of the other, Turano said.

About 15 minutes before Cisse was gunned down, Bracey and Warren had held up two other U of C students as they left the college library. They stole the womens’ pens, credit cards and wallets, Turano said.

After Cisse was shot and the men fled, the credit cards were used to buy gas to fill up the Bonneville.

MORE NEWS: Cook County Sheriff's Officer Fires Shots During Attempted Traffic Stop: Police

The Sun-Times Media Wire contributed to this report.