CENTENNIAL, Colo. -- The mother of Andrew Graham, a University of Colorado, Boulder graduate who was mysteriously gunned down in his parents’ quiet Centennial neighborhood, is speaking out in hopes that someone with information will come forward.

Cynthia Gelston Graham sat in her Centennial home wearing all black, a torn black ribbon affixed to her dress. It signifies grief in the Jewish mourning ritual.

“He was just beginning to discover what life was,” she said tearfully.

Gelston Graham said Andrew had a “brilliant” mind. At 23, the magna cum laude CU graduate was about to enter a master’s program in mathematics and engineering.

Gelston Graham found out about her son’s murder after driving by the house where he was found dead. She had received a phone call from Arapahoe County authorities, saying that her son’s briefcase had been found in her neighborhood. Thinking that Andrew had simply lost it, she got in her car and went looking for him. What she found was a crime scene.

“As I was driving down that street, I saw the crime scene tape,” said Gelston Graham. “I knew. I knew then, before anyone told me, that something very bad had happened to my son.”

Andrew was on his way home to see his parents when he was shot in the torso. Neighbors have reported hearing a gunshot the night of the murder, but one week later, authorities still have no suspects and few leads.

“It's felt like an eternity,” said Gelston Graham. “As time goes by I can only hope that they can find something that will give them some clues as to how this happened.”

Clues have been scarce. The Arapahoe County sheriff has appealed to six people who were seen on surveillance video riding the light rail with Andrew shortly before he was murdered. He stressed that the individuals, who appeared to have very little contact with Andrew, are not suspects.

Gelston Graham said her entire neighborhood has been shaken and, with the murderer still at large, the community remains on edge. She said she knows authorities are working around the clock on the case, but that their only hope may be someone who saw what happened to her son.

“I want this to be over,” she said. “I want them to hopefully find who did this.”

The Graham family has set up a trust in Andrew Graham’s name. Checks can be made out to Cynthia Gelston.