QUINCY — U.S. Rep. William Delahunt, the former district attorney whose office investigated the fatal 1986 shooting of Seth Bishop by his sister Amy, said Monday he does not feel his office “bears any responsibility” for Bishop being freed without charges. In a telephone interview with the Patriot Ledger, the Quincy Democrat said State Police Trooper Brian Howe correctly concluded that Amy Bishop shot and killed her 18-year-old brother, Seth, by accident. But Delahunt said he has “very serious concerns” that Braintree police never alerted Howe or his prosecutors that, after the shooting, Amy Bishop fled with a loaded shotgun...