Brazill's mother hands out gun locks Thursday, April 22, 2004 RIVIERA BEACH -- If the gun Nathaniel Brazill used to kill his seventh-grade teacher on the last day of school had been equipped with a safety lock, his mother, Polly Powell, might not be here knocking on doors and Brazill might not be in prison. Powell, of Lake Worth, walked the Stonybrook apartment complex at 1555 Martin Luther King Jr. Blvd. Wednesday, passing out gun locks to whoever would accept them. A day earlier, Primrose Walker, the mother of David Walker, the 14-year-old who was shot and killed by a...