MIAMI, Florida (WABC) -- Lavon Walker was a giant on the streets of Crown Heights. Walker counted out the victims of deadly gun violence for the acclaimed anti-violence group 'Save Our Streets'. This weekend, Walker was, himself shot to death in Miami.Authorities are seeking three men who were seen fleeing a diner, where Walker was murdered at 7 a.m. on Sunday. The motive in the shooting is still unclear."He's a superman, he's a superman," said Save Our Streets Co-Founder Derick Scott.Scott says Walker's death is 'unimaginable.Walker was 30-year-old - he w was a young man who rose from a life of gang violence in the streets. He was determined to save others, and to help them take their lives in another direction."Lavon was a strong young man...that's why he was loved," added Scott.'Save Our Streets' released a statement Monday saying,