A Bridgeport mother who lost her 19-year-old son to gun violence is hoping that five years after his death, someone who knows something will come forward and ease her pain. Lisa Diaz's son, Edgardo Defre, was shot and killed at the corner of Glendale Avenue and Peet Street back in September 2007. Police never arrested the teen's killer and the case has gone cold. Defre would have turned 24 this week, and his mother says she's convinced that someone knows something more about what happened. Diaz, who has multiple sclerosis and is confined to a wheelchair, says she's praying that someone will come forward and give her some closure. Bridgeport police are urging anyone with information to contact them at 203-581-5100.