On the eve of the one-year anniversary of the massacre at Sandy Hook Elementary School, a similarly terrifying scene played out at a Colorado high school.
One student was critically injured when a gunman entered Arapahoe High School Friday afternoon hunting for a teacher.
The Arapahoe County sheriff emphasized that there was no indication that the timing of the latest school shooting was anything other than coincidence, but the images making the airwaves Friday nonetheless were chillingly familiar: law enforcement flooding the campus, frightened students and faculty evacuating, emotional reunions between terrified parents and their children.
Arapahoe High School, located in Denver suburb Centennial, is also just 8 miles from Columbine High School in Littleton, where 12 students and one teacher were killed in another of the worst school shootings in U.S. history.
Authorities say the gunman, who was identified as 18-year-old Arapahoe High student Karl Pierson, reportedly made no effort to hide his shotgun when he walked into the school around 12:30 p.m. Friday. He starting asking students in the area if they had seen the teacher he was looking for.
The situation was over within minutes; Pierson's body was found by authorities in a classroom at 12:38 p.m. Law enforcement is still trying to piece together what happened in the seven or eight minutes between the time that the suspect entered the school and the time that his body was found.
What authorities do currently know is that word immediately got around that Pierson was asking for a specific teacher by name. The sheriff's office says the teacher left the building in an attempt to diffuse the situation, something Sheriff Grayson Robinson said may have prevented the shooting from being worse.
"It was a wise tactical decision," Robinson said.
The suspect then shot 17-year-old Claire Davis. A classmate says right before she was shot, she tried to convince the suspect to end the situation.
"She tried to talk him out of this, saying 'Karl, why are you doing this, this doesn't have to happen,'" August Clary told 11 News.
Davis was rushed to the hospital, where her condition has been downgraded from serious to critical following surgery. Governor John Hickenlooper told CBS' "Face the Nation" Sunday that Davis was in a coma.
A second student was believed to have been shot, but Robinson said that once the student got to the hospital, it was determined she was covered in Davis' blood, but not injured herself.
A school resource officer reported the shootings to the Arapahoe County Sheriff's Office at 12:33 p.m. Authorities found Pierson's body in a classroom at 12:38 p.m.
Robinson said Saturday that Pierson shot himself 80 seconds after the situation began.
Students and faculty were slowly evacuated from the campus. Authorities said that until it was confirmed there was no other shooter or any further danger to those inside the school, students and staff were safer locked inside their classrooms. The school was completely evacuated and students bused off campus by 3:30 p.m. Students were taken to a nearby middle school and a nearby church to be reunited with their families.
"My wife called absolutely frantic," one parent told KCNC. He tried to drive to the school; when he couldn't get anywhere near it, he said he went a back way and jumped "a bunch of fences" to get there. As the first parent on scene, he said began fielding numerous calls from frightened parents wanting to know if their children were okay.
The father of two said it was awhile before he knew that his own children were uninjured and accounted for.
"At first we couldn't get ahold of them [his children]," he told KCNC.
One woman, who was family friends with a teacher killed in the Columbine High School shooting in 1999, told the Associated Press her 15-year-old daughter texted her at 12:41 p.m. The text read: "There's sirens. It's real. I love you."
"I didn't hear from one of my daughters for over an hour," another mother told 11 News.
Shaken students, many crying as they spoke with 11 News and KCNC, described the moments after the shooting as terrifying.
"Am I going to get out? What's going to happen when I do?" one student told KCNC.
"It didn't seem real until I heard many, many ambulances," another student told 11 News.
Three students reportedly suffered anxiety attacks in the aftermath of the shooting. One had to be hospitalized, but was released a few hours later.
A bomb squad was called to the scene after authorities received information that there could be at least one explosive device inside the school. Two devices believed to be Molotov cocktails were found in the building. One had been detonated.
Investigators are now searching areas of the school that Pierson frequented and had access to.
Late Friday evening, investigators and a police dog entered the teen's home in Highlands Ranch. They are also talking to the suspect's family, friends and associates.
KCNC spoke to a student who said he knew Pierson. He was stunned the person he knew could have shot two fellow students.
"He was a charming kid, a little geeky, but a nice guy," he described, adding that the suspect had been demoted a spot on the debate team.
"No one saw this coming."
Robinson said that authorities are investigating the possibility that Pierson was targeting the teacher as revenge over a controversy or disagreement. When asked during a news briefing Friday if authorities believed the issue between the student and teacher was something serious, Robinson said not necessarily.
"If you look at the history of these tragic incidents, it takes something very little" to trigger something like the shooting, Robinson said.
Hickenlooper also spoke the a news conference Friday afternoon. He called the shooting an "unspeakable horror in a place of learning."
The district attorney echoed Hickenlooper's sentiments at a later news conference Friday evening.
"Tens of thousands of parents dropped their kids off at school today, expecting to pick them up this afternoon."