NEW : Authorities check other unsolved cases for possible ties . Hannah Graham , a student at the University of Virginia , went missing last month . She was found dead in her apartment on Friday morning after she had been sexually assaulted and beaten by three men who were later arrested. DNA links the same suspect to 2009 case of Morgan Harrington , source says .
NEW : Authorities check other unsolved cases for possible ties . Hannah Graham , a student at the University of Virginia , went missing last month . Police have Jesse Matthew in custody as a suspect in Graham 's disappearance . DNA links the same suspect to 2009 case of Morgan Harrington , source says .