State police crime-scene Sgt. Mary Ritchie holds up the alleged murder weapon. (AP/pool)

State police crime-scene Sgt. Mary Ritchie holds up the alleged murder weapon. (AP/pool)

Massachusetts State Police Sergeant Mary Ritchie holds up a weapon presented as evidence in the murder trial of Neil Entwistle at Middlesex Superior Court in Woburn, Mass., Thursday June 12, 2008. Entwistle, born in England, is charged with first-degree murder in the death of his wife, Rachel, and infant daughter, Lillian, in their Hopkinton, Mass., home in January 2006. (AP Photo/Brian Snyder, Pool)