Edward Russell Jr., of Gary, a Westville Correctional Facility inmate already facing four pending murder charges, is now accused in a fifth homicide after investigators said DNA testing linked him to the 2001 stabbing death of Tonya Renee Armstrong. According to the probable cause affidavit, Armstrong was reported missing on March 7, 2001, after her boyfriend returned to their apartment in the 500 block of East 5th Avenue and found the door dama…