SAN BERNARDINO, Calif. (KABC) -- Elaine Roundtree keeps the ashes of her only son, Robert, close by because it is all she has left of her youngest of three children.Last November, Roundtree was shot to death while riding his bike home after working the late shift at a warehouse. He was at the intersection of Pepper Avenue and Spruce Street."Twenty-four years old, never been in trouble. Never did anything wrong. He was just there for everybody. He was just happy-go-lucky Robby," Elaine Roundtree said.San Bernardino's west side is notorious for gang activity, which is where the intersection is located. To this day, Roundtree's murder remains unsolved.San Bernardino Police Department's Lt. Richard Lawhead said Roundtree did not have a police record."The victim in this particular case does not have a criminal history. He was basically a good kid on his way home from work...there's no gang affiliation. Just a kid riding his bicycle on his way home from work," he said.Investigators are asking for the public's help to find his killer. The department has several people of interest, but they need more information.Elaine Roundtree hopes someone will come forward and bring her son's killer to justice."We know somebody knows, and it's just hard living everyday knowing there's somebody out there that knows what they did. Nobody's saying anything," she said.The San Bernardino Police Department is asking anyone with information to contact the homicide unit at (909) 384-5615.