Authorities have released more details about the shooter who killed two students at a high school in Aztec, New Mexico, on Thursday morning. A police investigation has revealed that he planned the attack in advance. The 21-year-old man was an Aztec resident and had attended the school in the past. He gained access to the building by disguising himself as a student. Once inside, he used a handgun to shoot and kill two students in the hall before firing shots into walls and windows in an attempt to hit students in classrooms. He was killed by a bullet wound that is believed to have been self-inflicted. Locals held a candlelight vigil Thursday evening in remembrance of the boy and girl who died.