One year ago today, Weymouth Police Sgt. Michael Chesna was killed while investigating reports of an erratic driver. Police say a man threw a large rock at Chesna, grabbed his gun and repeatedly shot him. Chesna served for six years and was an Army veteran. He left behind a wife and two children. Click HERE to read Sergeant Chesna's complete story on the "Officer Down Memorial Page" and leave a message to honor his memory. Click HERE a letter from the family of Sergeant Chesna for the anniversary of his death. The family submitted this letter for publication at the invitation of The Patriot Ledger.