CHICAGO (AP) – A teenager was charged Wednesday in a series of violent crimes around the University of Chicago campus, including the fatal shooting of a Bates College graduate who was just weeks away from receiving his doctoral degree in chemistry.

Eric Walker, 16, of Chicago, gave a videotaped statement with a parent present admitting his role in the crimes, police said.

Walker was charged with first-degree murder, attempted robbery with a firearm, and one count of aggravated discharge of a firearm in connection with the shooting of Amadou Cisse, 29, said police spokeswoman Laura Kubiak.

Cisse, a native of Dakar, Senegal, graduated from Bates College in Lewiston, Maine, in 2001 with degrees in chemistry, physics and mathematics.

At the University of Chicago, Cisse was a graduate student and a teaching assistant for general chemistry classes.

He was shot in the chest steps from his home near the university on Nov. 19. It happened less than an hour after a university staff member was shot at while walking nearby and two female students were robbed at gunpoint, police said.

The teen also was charged with three counts of armed robbery in connection with those attacks, Kubiak said.

Walker lived about five miles from where Cisse was shot, police said. He did not have a published phone number, and authorities did not immediately know if he had an attorney.

Cisse earlier this month successfully defended his dissertation, a study of how molecules diffuse and migrate through polymers.

“He was an extraordinary young scientist and an extraordinary young person who would have contributed enormously to the world,” said Henry Webber, the university’s vice president for community and government affairs.

Cisse’s mother, two brothers and a sister live in Dakar, the nation’s capital.

The University of Chicago invited the family to send a member to accept the degree on Dec. 7, offering to pay the expenses, according to Cisse’s 27-year-old brother, Alioune, a computer engineer. But Cisse’s mother said no one would travel from their home in Dakar, Senegal, to pick up the degree.

“No, no, no, absolutely no. I will not come,” Seynabou Cisse, a pediatric nurse and widowed mother of three told the Chicago Sun-Times.

“It has hit my family very hard,” she added. “I am not coming to America. I just can’t.”

Cisse’s father, a military officer, was killed in Gambia.

“Our father died outside of the country. Now Amadou. So my mother is in shock,” Alioune told the newspaper. “My mother was asking me this afternoon if the death penalty exists in Chicago. That’s how angry we are here.”

His brother’s body, shipped home by the university, arrived Friday in Dakar, and the Muslim family held a small burial service, Alioune said.

Webber said university officials are working to improve campus security. A university police substation opened Wednesday about two blocks from where Cisse was shot, and campus patrols are being increased between dusk and dawn.