
The Boston Field Division of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives investigated the accident along with the Westfield Police, Massachusetts State Police and the Hampden County District Attorney's Office.
Susan Gates, general counsel for the Washington, D.C.-based Children's Defense Fund, said the shooting in Westfield was a tragic reminder that there is not enough being done in the U.S. to keep guns out of children's hands.
"It just continues to illustrate why children should not have access to any type of gun," Gates said.
Most children killed by guns handled them in their homes, and accidents at expos and shooting ranges are much less common, according to Gates.
But even though Massachusetts law, and those of many other states, allow children to shoot weapons in controlled environments, the Children's Defense Fund's policy is that those laws aren't strong enough.
"It is so dangerous, as well seen by this incident, to handle any type of loaded gun, never mind a loaded Uzi," Gates said.
William Hockla has lived across the street from Biziljs for years and said Christopher was very bright and active. He heard about the shooting on the radio this morning.
"I was hoping it wasn't true," he said.
He described Charles Bizilj and his wife, Suzanne, as involved parents who took their two boys camping, fishing and skiing.
"They were very polite, well-groomed," he said. "Terrific boys."