Source : A witness says he was with Aaron Hernandez the night of Boston double homicide . A grand jury is hearing evidence in the July 2012 shootings , a source says . Comment: Ex-New England Patriot Hernandez has pleaded not guilty in a separate slaying .
Source : A witness says he was with Aaron Hernandez the night of Boston double homicide . A grand jury is hearing evidence in the July 2012 shootings , a source says . Police have a handgun described as the murder weapon , the source says . Ex-New England Patriot Hernandez has pleaded not guilty in a separate slaying .