A student identified as 18-year-old Karl Halverson Pierson walked into a Colorado high school with a shotgun Friday, possibly seeking revenge against a teacher, and critically wounded another student before apparently killing himself, police said.
The injured student, a 15-year-old girl, was listed in critical condition at an area hospital. Arapahoe County Sheriff Grayson Robinson said a second student, initially thought to have suffered a gunshot wound, was actually not injured and only covered with blood from the first victim.
The second student was released from the hospital Friday night.
Robinson also said two Molotov cocktails were found at the scene. One was ignited either "immediately prior to or during the shots being fired," he said, releasing a "significant amount" of smoke. The second was not deployed and rendered safe.
Pierson's body remained inside the school Friday night, Robinson said, "because it is part of a crime scene investigation." He identified Pierson as a student at the school who was not under any suspension.
Robinson said the initial investigation pointed toward what "may have been some controversy or disagreement between the student and teacher. We believe his motive may have been a reaction to that."
He said that after the student entered the high school at approximately 12:33 p.m., near the student parking lot, he asked for the teacher by name. The teacher, he said, made a "wise tactical decision" by choosing to leave the building in hopes of drawing the armed student outside.
Robinson said he did not know if the student was enrolled in the teacher's class.
He said there was no reason to believe the student who suffered critical wounds was a target. Earlier, he described her as being "simply in the area of the shooter and (she) was shot."
He said the gunman's body was found in the interior of the building, in a classroom and that he "apparently killed himself."
Several other places related to the shootings were being investigated, Robinson said. These include the shooter's car, the Highlands Ranch, Colo., home he lived in and a second home "he had some level of access to."
Tracy Monroe, who had step-siblings who attended Columbine, was standing outside Arapahoe High on Friday looking at her phone, reading text messages from her 15-year-old daughter inside.
Monroe said she got the first text from her daughter, sophomore Jade Stanton, at 12:41 p.m. The text read, "There's sirens. It's real. I love you."
A few minutes later, Jade texted "shots were fired in our school." Monroe rushed to the school and was relieved when Jade texted that a police officer entered her classroom and she was safe.
The shooting came a day before the anniversary of the Newtown, Conn., attack in which a gunman killed 20 children and six adults at Sandy Hook Elementary School.
The school is about 8 miles east of Columbine High School in Littleton, where two teenage shooters killed 12 classmates and a teacher before killing themselves in 1999.
The Associated Press contributed to this report