At 1:54 p.m. Tuesday, an alarm blared across Douglas County first responder radios and a dispatcher called all units to STEM School Highlands Ranch.

“Attention all units getting information of a shooting at STEM School,” a dispatcher said.

For the next 14 minutes, law enforcement rushed to STEM School and searched for the shooters. There was early confusion about the number of shooters and the descriptions of what they looked like. Still, law enforcement confirmed they had the the first suspect in custody less than seven minutes after the first call was aired and the second suspect in custody in a separate part of the building about seven minutes later.

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“It was a very confusing situation,” Douglas County Sheriff Tony Spurlock said Wednesday at a news conference.

Following is a brief timeline of the response to the school in the immediate aftermath of the shooting, based on archived scanner information:

1:53 p.m.: A dispatcher alerts all units to a report of a shooting at the school and directs responding officers to a first-floor room.

1:54 p.m.: A dispatcher reports that one person has been shot in the lower back and at least three are injured.

1:56 p.m.: The first law enforcement officer confirms he is on scene and a dispatcher airs a description of one suspect with pink hair.

1:58 p.m.: An officer on scene reports there are more gun shots in the building and others start to find injured students.

2:00 p.m.: An officer confirms they have a shooter in custody in a classroom.

2:03 p.m.: Officers confirm with the first shooter in custody that a second shooter is still on the loose.

2:07 p.m.: Officers say they have both shooters in custody but warn there might be a third. Law enforcement officers soon realize there is not a third suspect.

Police rushed into the school immediately after arriving. Three students had tackled one of the gunmen in a classroom and disarmed him, according to student accounts. Senior Kendrick Castillo died in the school after he helped tackle the gunman.

A security guard contracted by the school was able to restrain that suspect until deputies arrived.

Law enforcement did not exchange gunfire with the teen suspects, Spurlock said, though a security guard may have fired shots during the incident.

For the next 20 minutes after arresting both suspects, officers cleared the school and looked for wounded students and staff. By about 2:15 p.m., officers from agencies all over the region had responded to the school.

“We don’t need any more cops here we got enough now,” one officer said.

One officer said he had a group of students run to him as he cleared the school. Cops found those who were injured — one with a gun shot to the foot and another who was shot in both legs. Ultimately, eight students were injured in the attack.

The officers checked classrooms, lockers and crawl spaces looking for students who had hid. As they cleared classrooms, they marked them with an “X”.

Later that night, officers searched the home of the 18-year-old suspect and towed away a car.

Officials had not publicly identified a motive for the shooters as of Thursday evening and many details about what happened during the shooting remain unclear.

Both shooting suspects are scheduled to appear in court Wednesday morning.