Suspected serial killer linked to 3 more murders at North Dallas nursing home Suspected serial killer linked to 3 more murders at North Dallas nursing home A suspected serial killer has three new murder charges, bringing the deaths he’s accused of to 17 in Dallas and Collin counties. DALLAS - A suspected serial killer has three new murder charges, bringing the deaths he’s accused of to 17 in Dallas and Collin counties. Police say Billy Chemirmir killed residents at senior living facilities and stole their belongings. What’s even more incredible is there are still other deaths he’s suspected of but hasn’t been formally charged with.