Disturbing past: Thomas Crooks' troubled school years revealed

The media have reached out to Thomas Crooks' former schoolmates. Students describe him as an "outcast" who was "bullied every day." It turns out that the 20-year-old wanted to join a shooting club during high school but was unsuccessful. "His shot was so weak that he was considered dangerous," his schoolmates recount.

The Daily Mail published a recording in which one of the men talks about what Thomas Matthew Crooks was like in school. "He was a kid who was always alone, always bullied, every day," says former classmate Jason Kohler.

"He was an outcast. I mean, he sat alone during lunch at school. You know how kids are these days. Honestly, it's really sad. I don't want to say it provoked him, but you never know," the man says.

ABC News also contacted people who attended Bethel Park High School with Crooks. Former classmates described him as a "quiet" student who didn't have many friends. "One thing I knew for sure was that he was very smart," said a student who sat behind Crooks in AP statistics class.

"I always remember hearing his test scores when we all compared them. He always did very well, both in mathematics and sciences," he added.

According to Frederick Mach, the current team captain who attended the school a few years after Crooks, the 20-year-old tried out for the school shooting team. However, he did not make it because he shot poorly.

Jameson Myers, a team member at the time when Crooks was being evaluated, said there was something disturbing about him even then. "Not only did he not make the team, but he was also asked not to return because his shot was so weak that he was considered dangerous," Myers said in an interview with ABC News.

Classmate Jameson Murphy told the New York Post that Crooks once missed a target by nearly 20 metres. Other classmates pointed out that he made inappropriate jokes.

"We noticed a few things Thomas said and how he communicated with other people. He said some things that raised some concerns," said one classmate. "He told crude jokes that were not appropriate when there are firearms at school," they added.

However, Crooks was a member of the local shooting club, Clairton Sportsmen's Club. "I can confirm that Mr. Crooks was a member of Clairton Sportsmen's Club. Besides that, the club is unable to provide any additional comments in light of the ongoing investigations by law enforcement," said Robert S. Bootay III, the club's lawyer.