CENTENNIAL - The 18-year-old gunman who took his own life after shooting a fellow student at Arapahoe High School Friday was identified as Karl Halverson Piersen.
The 15-year-old female shooting victim is in critical condition. There was some initial confusion about a possible second shooting victim, but Arapahoe County Sheriff Grayson Robinson said later in the evening that the second victim had only appeared to have been shot.
A 15-year-old victim, who was in the immediate area of the gunman, was transported to a Littleton hospital in critical condition. That student is currently undergoing surgery.
The second victim who was initially thought to have been shot was transported to Swedish Medical Center in Englewood. There it was determined she was not shot. The blood found on her was from the first victim.
A third victim suffered an anxiety attack and was also transported to Swedish.
The Englewood hospital said both patients were released later in the evening.
Two other students suffered emotional attacks but were treated at the scene, according to Sheriff investigators.
Pierson was found dead inside the school from a self-inflicted gunshot wound, according to the police.
Suspected shooter's home searched
Police say Pierson - armed with a shotgun - entered the west side of the school around 12:30 p.m. and asked for a specific teacher by name.
Authorities said the Pierson made no effort to conceal the weapon when he entered the school. He was able to get "very deep" within the school.
The teacher, after learning that he was being asked for by the student and that the student was armed, immediately implemented "active-shooter protocols."
Active shooter protocols include evacuating the grounds in a safe manner and placing the school on lockdown.
About 20 minutes after police began searching Arapahoe High School, police found the Pierson dead in a classroom from an apparent self-inflicted gunshot wound. The body remains inside the school.
Police did not engage in a gunfight with Pierson.
Police believe the suspect acted alone, and there are no other threats at this time.
Arapahoe County Sheriff investigators are looking into revenge against the teacher Pierson was looking for as a possible motive.
Officials' response to school shooting
DEVICES FOUND IN SCHOOL
Two devices, being described as Molotov cocktails, were found inside the school. One device was detonated by Pierson; the other device was located and deemed safe.
Officers who arrived on scene had to deal with smoke from the first Molotov cocktail detonation.
A Molotov cocktail is a bottle-based improvised incendiary weapon.
Witnesses describe Arapahoe HS shooting
Students were seen walking toward the school's running track with their hands in the air. SKY9 showed students being patted down by police.
"The kids have been through a traumatic situation," Arapahoe County Sheriff Grayson Robinson said. "We need to ensure that anyone we evacuate isn't part of our problem. We're doing the evacuation slowly and deliberately."
9NEWS Reporter Meagan Fitzgerald said she saw many students sobbing on the athletic fields as they loaded buses to the church.
Parents showed up in all sorts of conditions - wearing tennis skirts and hospital scrubs - to pick up their kids.
Arapahoe High School will be closed Monday. Arapahoe High School is a part of Littleton Public Schools. There are 70 different classrooms in the high school which covers a 254,000-square-foot area. There are 2,229 students that attend the high school. The school was built in 1964.