NEW : Shell Oil is a major oil company with operations in the United States, Canada, and Mexico. The suspect says he saw `` two monsters '' and shot them , according to an affidavit . Six weeks after the slayings , Oklahoma authorities released a 911 tape in which a breathless , nearly hysterical woman -- identified only as a family member of one of the victims -- is heard screaming , `` Somebody killed two girls . '' `` We just believe that he happened to be in the area that day , '' an investigator says . Sweat became a suspect in this case after being arrested this summer in his girlfriend 's death .
NEW : Shell Oil is a major oil company with operations in the United States, Canada, and Mexico. The suspect says he saw `` two monsters '' and shot them , according to an affidavit . `` We just believe that he happened to be in the area that day , '' an investigator says . Sweat became a suspect in this case after being arrested this summer in his girlfriend 's death .