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 .
NEW : Shell casings at crime scene matched those on suspect 's father 's land , police say . 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 .