Authorities say the gunman entered Arapahoe High School at 12:33 p.m. He entered on the west side of the school.
CENTENNIAL, Colo. (AP) -- Arapahoe High School students in Colorado are back in class for the first time since a fatal Dec. 13 shooting on campus.
The Denver Post reports principal Natalie Pramenko sent a letter to parents saying additional sheriff's deputies will be at the campus and extra school district staff members will be on hand to help students for Tuesday's reopening.
Students have not attended classes since senior Karl Pierson entered through a door that was propped open and fatally shot Claire Davis before killing himself.
Investigators believe his intended target was a speech coach who had disciplined him.
A tribute to Davis that sprung up on a fence outside the school is gone but students were greeted with the words "Love," "Hope" and "Warrior Strong" spelled out with cups there.
Arapahoe High School, state officials are reminding students about a hotline to report threats.
Attorney General John Suthers and state lawmakers are promoting the Safe2Tell hotline. It's an anonymous threat-gathering system created in 2004 for students and teachers to report threats and bullying.
State officials say the hotline has prevented more than two dozen school attacks since its creation.
The hotline was a recommendation of the Columbine Commission, a state panel that reviewed school safety after the 1999 shootings at Columbine High School.
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