1. Dec 8, 2017 1:56 PM EST: The shooting that left two students and a gunman dead in New Mexico on Thursday was planned ahead of time, authorities said at a news conference Friday.

    “He was determined to create as much carnage as he could,” San Juan County Sheriff Ken Christesen said.

    The sheriff shared a message posted by the shooter, identified as 21-year-old William Atchison, around 6:51 a.m. Thursday. Authorities said Atchison walked into Aztec High School after disguising himself as a student and mingling with crowds getting off school buses around 8:05 a.m. Thursday.

    According to Christesen, Atchison wrote, “If things go according to plan, today would be when I die. I’d wait until the school buses are detected then head out on foot disguised as a student. I’d go somewhere and gear up, then hold a class hostage and go ape (expletive), then blow my brains out.”

    Authorities also found a note in a trashcan in Atchison’s room that appeared to include a schedule of his plans for Thursday.

    “This person is not only a coward, he’s evil,” Christesen said. “In my mind, there’s so many things wrong with this.”
  2. Dec 8, 2017 1:37 PM EST: New Mexico State Police said the gunman who opened fire at Aztec High School on Thursday, identified Friday as 21-year-old William Atchinson, went first to a bathroom on the school's second floor after disguising himself as student and mingling with students outside.

    Atchinson entered Aztec High School just after 8 a.m. with a backpack containing a 9 mm Glock pistol and multiple magazines, investigators said.

    Inside a second floor bathroom, Atchinson found high school junior Francisco "Paco" Fernandez.

    "(Fernandez) had absolutely no chance to survive that encounter," state police Chief Pete Kassetas said Friday. "He never exited that restroom."

    Authorities said Atchinson found his second victim, senior Casey Marquez, in a hallway.

    "He immediately shot her dead," Kassetas said.
  3. San Juan County Sheriff Ken Christesen said after gunshots were heard and a lockdown was issued at the school, staff members became heroes. He described the situation for substitute teacher Kathleen Potter, 74, who was unable to lock her classroom door because, as a substitute, she had no key.

    She had 16 students in her care, Christesen said.

    "So she took all the kids and put them into an office area, in a supply room or storage (area), and they barricaded the door with a couch," Christesen said.

    He said Atchinson approached the room but couldn't get in.

    "(He) was hollering at them, 'I know you're in there,'" Christesen said. He then fired multiple rounds through the walls. No one was injured by the bullets.

    The sheriff said custodian Thomas Hill risked his life to follow the shooter, yelling for teachers to lock their doors.

    "These people are true heroes," Christesen said. "They're right here in our community."
  4. Dec 8, 2017 1:28 PM EST: San Juan County Sheriff Ken Christesen on Friday shared a message the gunman had written before the shooting on Thursday morning. It included a timeline of what the gunman had planned.

    Christesen called the shooting at Aztec High School a cowardly act and that the shooter was determined to create as much carnage as he could.

    Authorities said the gunman lived with his parents in Aztec and had worked at a gas station. In his message, he wrote that work, school and life was bad and he wanted out.
  5. Dec 8, 2017 1:18 PM EST: The FBI had previously investigated William Atchinson before the 21-year-old opened fire on students at New Mexico's Aztec High School on Thursday, officials said Friday at a news conference.

    The FBI opened an assessment in March 2016 after he made comments on an online gaming forum along the lines of asking what kind of weapon would be best if he planned to commit a mass shooting, authorities said. The assessment was closed after authorities determined that no laws were broken.
  6. Dec 8, 2017 1:13 PM EST: Authorities on Friday identified the gunman as a 21-year-old man who planned the shooting and disguised himself as a student to get into the school.

    Officials identified him as William Atchinson at a news conference Friday.
  7. Dec 7, 2017 1:13 PM EST: New Mexico state police confirmed that a suspected shooter and two students were killed Thursday morning in an attack reported at Aztec High School.

    No other injuries were reported, according to police.
  8. Original report: They were believed to be students at Aztec High School, where the shooting was reported Thursday morning, San Juan County Sheriff Ken Christesen told The Associated Press.

    He said it was not immediately clear whether the suspected attacker was among the three slain, although the Navajo Nation's Office of the President and Vice President said in a news release that two people were fatally wounded in the shooting.

    KRQE confirmed that two people believed to be students were killed along with the suspected attacker.

    “It’s tragic when our children are harmed in violent ways, especially on school campuses. We express our condolences to those families who have been harmed,” Navajo Nation President Russell Begaye said. “Our prayers go out to all those affected by this tragedy and everyone throughout San Juan County. We are asking for prayers for these families."

    Christensen told KOB that authorities were called before 8:45 a.m. MST to reports of a shooting at Aztec High School.

    Nearby schools were placed on lockdown in the wake of the attack, the Farmington Daily Times reported. Investigators with the FBI were on the scene Thursday morning.
  9. Check back for updates on this developing story.
  10. The Associated Press contributed to this report.