Students returned to classes at Arapahoe High School on Tuesday.
LITTLETON, Colo. - Arapahoe High School may be turned over to Littleton School District officials Sunday night.
Investigators have completed their work at the high school, Arapahoe County Sheriff Grayson Robinson told 7NEWS Reporter Russell Haythorn Sunday.
No classes are being held at Arapahoe High Monday. It is not clear when the school will reopen. The rest of the district is on the regular schedule.
Karl Halverson Pierson, 18, shot a fellow student inside the school, investigators said Friday night.
17-year-old Claire Davis was airlifted to Littleton Hospital.
She is in "very critical condition," Arapahoe County Sheriff Grayson Robinson said Sunday.
Pierson went into the school armed with a shotgun looking for the school's librarian, Tracy Murphy -- who was head of the school's speech and debate team and who had recently kicked Pierson off the team, sources told the CALL7 Investigators.
Pierson was found dead from an apparent self-inflicted gunshot wound 5 minutes after the deputy assigned as a school resource officer made an initial radio call about the "active shooter" situation inside the school, Robinson said.
Coverage: Arapahoe High School Shooting
Teachers and staff went back to work at Arapahoe High School on Monday. Students will return to classes on Tuesday.
An online petition drive is asking Littleton Public Schools to give Arapahoe High School shooting victim Claire Davis a diploma at graduation in May.
When an armed student went into Arapahoe High School on December 13, many people sprung into action.
Claire Davis' father asked people to forgive the fellow student who shot and killed his 17-year-old daughter at Arapahoe High School.
The Arapahoe High School shooter entered the school through a door that should have been closed and locked, but was left ajar, Arapahoe County Sheriff Grayson Robinson said.
Gov. John Hickenlooper orders flags lowered to half-staff Wednesday in honor of Claire Davis, the student slain in the Arapahoe High School shooting.
Tickets to the celebration of Claire Davis' life are now available for students and staff at Arapahoe High School.
Claire Davis will be celebrated next week with a memorial at the National Western Stock Show and Complex.
Prosecutors are warning people that scam artists may try to take advantage of the shooting death of Claire Davis at Arapahoe High School by setting up phony websites and requesting donations.