Demetrius Warren has been found guilty of first-degree murder in the 2007 slaying of University of Chicago graduate student Amadou Cisse. (August 23, 2011)

A Cook County jury late Monday convicted a man in the slaying of a University of Chicago doctoral student during a botched robbery nearly four years ago.

Demetrius Warren, 21, was found guilty of first-degree murder, armed robbery and aggravated discharge of a firearm, and faces a minimum of 82 years in prison when he is sentenced in October.

He was accused in the November 2007 shooting of Amadou Cisse, a Senegal native who was accosted by Warren and a crew of stickup men allegedly prowling the area around the Hyde Park campus looking to carry out "licks," or robberies.

Cisse, 29, had recently defended his dissertation in chemistry and was going to be awarded a Ph.D.

Cisse's mother and siblings in Senegal had received updates by phone and email throughout the trial. His godmother, Czerny Brasuell, who attended every day of the proceedings, said Monday that the guilty verdict might "help in the ongoing process of healing."

"Our grief is constant," Brasuell said in a statement after the verdict. "We will always be aware of the presence of his absence."

Assistant State's Attorney Mark Shlifka told jurors in closing arguments that Warren deserved "his own advanced degree — in first-degree murder."

"Amadou Cisse had a bright and promising future, he had the world seemingly at his fingertips," Shlifka said. "Now instead of Dr. Amadou Cisse, we have Demetrius Warren, Dr. Death."

Prosecutors said Warren had come up with the idea to rob people around the U. of C. campus and enlisted the help of co-defendant Eric Walker, who had rented a car from an acquaintance in return for crack cocaine.

Walker, who agreed to testify against Warren in exchange for a 20-year sentence for armed robbery, testified he drove around the university campus while Warren and two others picked out victims in the early morning hours of Nov. 19, 2007.

Defense attorney Richard Kling urged the jury to reject Walker's testimony, noting the plea deal with prosecutors provided and incentive for him to lie, and that his stories to police and prosecutors changed over time.

Two other defendants, Benjamin Williams and Jamal Bracey, pleaded guilty to the murder last year. Judge Dennis Porter sentenced Williams to 53 years in prison, and gave Bracey a 35-year term.

jmeisner@tribune.com