A student who was required to be patted down at the start of each school day allegedly shot and wounded two school administrators at East High School in Denver, authorities said.
The suspect, Austin Lyle, 17, fled the school after the Wednesday morning shooting, Denver police said. His body was discovered in nearby Park County on Wednesday night after an hours-long manhunt, officials said.
"We're going to connect with the parents of Austin this evening," Denver Public Schools Superintendent Alex Marrero told reporters during a press briefing Thursday afternoon. "I can acknowledge that we failed Austin as a district."
Lyle allegedly shot the school administrators as they patted him down in the school's office area, which officials said is away from other students and staff.
The injured faculty members were both hospitalized. Eric Sinclair remains in serious condition and Jerald Mason has since been released from the hospital, according to the hospital and school district.
The suspect's daily searches were part of a "safety plan" that was a result of "previous behavior," officials said at a Wednesday news conference.
Marrero said that the school had a "regular routine" with the student, but on the day of the shooting the administrator who typically engaged with the student was not available and two different staffers were involved in the pat-down.
Last year Lyle was expelled from Overland High School in Aurora for allegedly violating school policy, a spokesperson for the Cherry Creek School District told ABC News.
Law enforcement sources told ABC News that in 2021 Lyle was charged with possession of a dangerous weapon.
It is unclear if that is the same incident that led to his dismissal from Overland High School, but sources told ABC News that school leadership described Lyle to police as "potentially violent" and a "threat to the safety of the school" after a series of events in the 2021-2022 school year, including bringing a weapon to Overland High School prior to his dismissal.
This year at East High School, Lyle appeared to be a "loner" who didn't seem to have friends, according to two East High School students who did not want to be named.
For East High School, Wednesday wasn't the first incident of gun violence for the school this year.
Last month, East High School students went to a city council meeting to call for action on school safety and gun violence after a 16-year-old student was fatally shot near the school, according to ABC Denver affiliate KMGH.
Superintendent Marrero said Wednesday that the school will be closed for the rest of this week, and that the building will now have two armed officers present through the end of the school year.
Denver Mayor Michael Hancock, in a statement, said removing school resource officers was a "mistake" and said they should be quickly returned.
On Thursday, the Denver Board of Education also voted to suspend a policy that prevented armed police officers from being inside the district's schools. The memorandum will suspend the policy through the end of the academic year.
Marrero announced Thursday that all district schools will be closed Friday for a "mental health day."
"I want to extend my heartfelt apologies to the East High School community and the larger DPS community," he said in a letter. "No student or employee should have to carry the fear of potential violence when they walk into our buildings each day."
Marrero encouraged students to "pause and process the challenging events this year" and provided contact information for multiple support services.
He noted that among the year's "challenging events" was a significant data breach this month that comprised many employee names, Social Security numbers, bank account numbers, driver's license numbers and passport numbers. The breach was unrelated to the shooting.
White House press secretary Karine Jean-Pierre told reporters Wednesday that the administration's "hearts go out to the families of the two school administrators and in Denver today and to the entire school community."
Jean-Pierre noted that President Joe Biden unveiled another executive action aimed at tackling gun violence last week but that "as the president said in the State of the Union, Congress needs to do something."
The mayor also called on Congress to pass "common sense" gun legislation.
"Parents are angry and frustrated, and they have a right to be," he said. "Easy access to guns must be addressed in our country -- Denver cannot do this alone."
This shooting comes two years to the day after a mass shooting at a King Soopers grocery store in Boulder, Colorado, that claimed 10 lives.
ABC News' Nic Uff and Ahmad Hemingway contributed to this report.