williamatchison San Juan County, N.M., Sheriff's Office
William Atchison, 21, of Aztec, N.M.

21-year-old ex-student identified as killer in New Mexico high school shooting

William Atchison disguised himself as a student at Aztec High School to enter the building.

Police have identified a 21-year-old former student who entered a high school in New Mexico and shot two students to death. 

William Atchison, 21, disguised himself as a backpack-carrying student at Aztec High School in Aztec, N.M., on Thursday as school buses were dropping students off for morning classes. He fatally shot two students, Casey J. Marquez, a senior, and Francisco I. Fernandez, a junior, then took his own life.

Atchison lived in Aztec with his parents and worked at a local gas station.

"He planned this thing," San Juan County Sheriff Ken Christensen said at a Friday news conference.

In a note written early Thursday that police found on a thumb drive in Atchison's possession after the shootings, the gunman wrote: “If things according to plan, today would be the day that I die.”

Atchison then described his plan to disguise himself as a student as buses unloaded, “go somewhere and gear up, then hold a class hostage and go apes—t, then blow my brains out….Work sucks, school sucks, life sucks. I just want out of this…”

Investigators say Atchison, after gaining access to the school, entered a bathroom on the second floor to prepare for his attack. He was armed with a 9 millimeter glock.

The first victim, Francisco Fernandez had left his class to go to the bathroom, where he encountered Atchison, who opened fire on him. Atchison then left the bathroom and shot Casey Marquez to death in the hallway.

Atchison continued to fire shots as went up and down the hallway, but no one else was injured as the school went into lockdown.

“By all indications, we believe he takes his own life, using that very gun,” New Mexico State Police Chief Pete Kassetas said.

Facebook video of Friday news conference (San Juan County Sheriff's Office):

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.