The teenage gunman who entered Arapahoe High School on Friday afternoon and shot two fellow students with a shotgun was outspoken about politics, was a gifted debater and might have been bullied for his beliefs, according to students who knew him.

Arapahoe County Sheriff Grayson Robinson identified the gunman as Karl Pierson, an 18-year-old student.

“He had very strong beliefs about gun laws and stuff,” said junior Abbey Skoda, who was in a class with Pierson during her freshman year. “I also heard he was bullied a lot.”

Robinson said that his department was investigating reports that Pierson was seeking to settle a score with a teacher after a confrontation.

Even before authorities named the gunman, friends and neighbors were in shock as word spread that Pierson was a dedicated, bright student from a religious family that attends Bible study meetings.

“They’re just a normal middle-class family, like many of the families around here,” said neighbor Diane Shea.

On Friday night, neighbors huddled in the quiet Highlands Ranch neighborhood adorned with holiday lights to console one another.

Neighbors and students remembered Pierson as a track athlete and a member of the Arapahoe speech-and-debate team whose mother worked for the Douglas County School District.

In April, Pierson placed third in national extemporaneous speaking at the National Qualifying Tournament held at Cherry Creek High School, earning him a spot in the national tournament in June.

After the June competition, he wrote on Facebook: “Hey guys! I just got back from day 2 of nationals and I’m sorry to say I am not moving on, nor am I in the top 60 in the country. Thank you from everyone for your support, and have a great rest of the summer and hope we can send some more guys to nationals in Kansas next year!”

Jo VanDeWege, who has lived across the street from the family for five years, described Pierson’s mother as outgoing and said the family was “very nice, very kind.”

Pierson’s parents divorced in late 2011, according to court records. The divorce was finalized in August 2012.

Thomas Conrad, who had an economics class with Pierson, described him as very opinionated.

“He was exuberant, I guess,” Conrad said. “A lot of people picked on him, but it didn’t seem to bother him.”

In one Facebook post, Pierson attacks the philosophies of economist Adam Smith, who through his invisible-hand theory pushed the notion that the free market was self-regulating. In another post, he describes himself as “Keynesian.”

“I was wondering to all the neoclassicals and neoliberals, why isn’t the market correcting itself?” he wrote. “If the invisible hand is so strong, shouldn’t it be able to overpower regulations?”

Pierson also appears to mock Republicans on another Facebook post, writing “you republicans are so cute” and posting an image that reads: “The Republican Party: Health Care: Let ’em Die, Climate Change: Let ’em Die, Gun Violence: Let ’em Die, Women’s Rights: Let ’em Die, More War: Let ’em Die. Is this really the side you want to be on?”

Carl Schmidt and Brendon Mendelson, both seniors at Arapahoe High, knew Pierson. They said he had political views that were “outside the mainstream,” but they did not elaborate.

Schmidt said the shooter “was an outspoken kid about what he believed and a good political thinker.”

Mendelson added, “He did have a lot of friends. He was popular with the people he knew.”

Staff writers Sadie Gurman, Kevin Simpson and Kurtis Lee contributed to this story.

Zahira Torres: ztorres@ denverpost.com or 303-954-1244