Timeline Of Events: Arapahoe High School Shooting

Emotional reunion between parents and Arapahoe High School student (Credit: KCNC)

-On December 6, suspected gunman Karl Pierson, 18, legally purchased a shotgun and several rounds of ammunition.

-December 13, lone gunman entered Arapahoe High School around 12:30 p.m. asking for specific teacher by name.
-Gunman, believed to be Pierson, entered through the west side of the school.

- Teacher heard student was looking for him and left the school immediately in an effort to encourage the shooter to leave the school.

- A 17-year-old girl was shot. She was rushed to the hospital, where she underwent surgery and is now in critical condition. She has been identified as Claire Davis.

-School resource officer reported the shooting to the Arapahoe County Sheriff's Office at 12:33 p.m.

-Students and faculty locked themselves inside classrooms waiting to be evacuated.

-Arapahoe County Sheriff Grayson Robinson says the sheriff's office activated "active shooter" protocol immediately. Authorities entered school within a couple of minutes of receiving the call from the school resource officer.
-Governor Hickenlooper said that because of past shootings, Denver-area officers were specifically trained in handling school shootings.

-Body of shooter was found by school resource officer and other responding deputies in a classroom at 12:38 p.m. Authorities now believe he shot himself 80 seconds into the incident.

-Authorities spent more than two and a half hours "very slowly, deliberately and meticulously" evacuating the entire school and busing students to reunification sites. Grayson explained they had to make sure everyone was safe, and that there were no other suspects or collaborators. Grayson says while authorities searched the school, students and faculty were safest staying in place.

-Entire school was evacuated and students off campus by 3:30 p.m. Students were taken by bus to Shepherd of the Hills church and Euclid Middle School on Euclid Avenue, where they were reunited with their parents.

-School expected to be an active crime scene through at least Sunday night. Authorities are now searching areas of the school that the suspect frequented and had access to. They are also searching his home, and talking to the suspect's family, friends and associates.

-Confirmed at 6 p.m. Friday: Two Molotov cocktails were found inside the school. One was detonated.

This timeline will continue to be updated as authorities release more details about how the shooting unfolded.