The father of a teenager suspected of fatally shooting three students at a high school in Michigan on Tuesday is believed to have purchased the semiautomatic gun used in the attack just days ago, authorities said. A boy and two girls were killed in the shooting incident at Oxford High School in Oxford, Michigan. They have been identified as 16-year-old Tate Myre, 14-year-old Hanna St. Juliana, and 17-year-old Madisyn Baldwin. Eight others, including a teacher, sustained gunshot wounds in the attack, according to authorities. Oakland County Sheriff Michael Bouchard told reporters at a news conference on Tuesday night that law enforcement officials believe the 9-millimeter Sig Sauer pistol used in the attack was purchased by the suspect’s father on Nov. 26, four days before the shooting incident. Bouchard said the suspect had at least two 15-round magazines. Two were seized by law enforcement officials at the scene but he is believed …