PARKLAND, Florida—Nikolas Cruz, the man accused of killing 17 people in a Florida high school, was a member of a “white separatist paramilitary proto-fascist organization,” a leader of the group told The Daily Beast.

Cruz, 19, is accused of opening fire inside Marjory Stoneman Douglas High School in Parkland, Florida. Jordan Jereb, a captain of the Republic of Florida, said Cruz trained with the group (as first reported by the Anti-Defamation League).

Broward County Sheriff Scott Israel said Thursday evening that the claim is “not confirmed at this time” but “we are looking into that.” After previous mass shootings, the alt-right has spread disinformation online about alleged perpetrators.

Jereb claimed Thursday morning Cruz was a part of the Republic of Florida.

“This is a difficult subject,” he said. “I’ve been taking calls all day on it. I’m many things, but I’m not a liar. I can’t lie. He was part of our organization. He wasn’t particularly active in it, but at some point he came to Tallahassee with I believe the Clearwater RoF. I know he didn’t live in Clearwater, but I think that was the company he clicked up with.”

After taking a moment to check notes, Jereb confirmed Cruz came to Tallahassee with the “secretive cell” from Clearwater.

“They called him ‘Nick,’ they didn’t call him ‘Nikolas,’” he said.

“I’ve been in the same room as the guy but I don’t know the guy,” he said. “I don’t know precisely what he believes. I know he knew full well he was joining a white separatist paramilitary proto-facist organization. I know he knew that much.”

RoF was recently operating in Tallahassee and attempting to court new members, according to a local news report from last year. The group posts videos of training montages on the internet with members in fatigues brandishing weapons.

“I’m not trying to glorify it, but he was pretty efficient in what he did,” Jereb said. “He probably used that training to do what he did yesterday. Nobody I know told him to do that, he just freaked out.”

Cruz received at least one of his guns through the white supremacist group, according to Jereb.

“I think somebody bought him a Mosin–Nagant, but that’s bolt action. He had a semi-automatic in the school,” Jereb said.

Cruz bought the AR-15 rifle authorities say he used at the school in February 2017, the ATF said in an affidavit filed Thursday.

Jereb said Cruz “seemed like just a normal, disenfranchised, young white man.”

While no motive has been described by police, Jereb speculated that Cruz may have allegedly committed the massacre out of hatred for Jews or women.

“There’s a very real sense of feminism being a cancer. That could’ve played into what he did, but we have female members of RoF,” Jereb said, adding that “we’re not a big fan of Jews. I think there were a lot of Jews at the school that might have been messing with him.”

Last year, an alleged school shooter in New Mexico also expressed alt-right ideology online, as The Daily Beast previously reported.

Hate in High School

Seven classmates of Cruz told The Daily Beast he expressed extreme political views and disturbing behavior when he attended the high school he is now accused of attacking with a high-powered rifle.

“The one person I would expect to do it did it,” said Julianna Sivon, who said she sat next to Cruz in English class last year. “He loved talking about his guns. He just didn’t seem right, but he didn’t seem like he would do something this big.”

Kamrie Bazal, 19, and Damar Osouna, 19, said they knew Cruz in school and that he talked about about guns but they did not suspect he would kill. Daniel Journey, 18, said Cruz was a troublemaker who was kicked out of class once for smashing windows.

Nyla Hussain, a 16-year-old junior, said her good friend sat next to Cruz in biology class last year and that he would regularly show her photos of dead animals.

“Whoever he sat next to in class he would show pics of animals that he hunted,” she said.

Two classmates said they saw Cruz wearing a “Make America Great Again” hat.

“I saw him wear a Trump hat,” said Sebastian Gonzalez, a 19-year-old who graduated in 2017.

Ocean Parodie, a 17-year-old junior, said Cruz was politically extreme.

“For example, he would degrade Islamic people as terrorists and bombers. I’ve seen him wear a Trump hat,” Parodie said.

Josh Charo, a 16-year-old junior who was in JROTC with Cruz, said he often expressed racist beliefs.

“He would always talk about how he felt whites were a bit higher than everyone,” Charo said. “He’d be like, ‘My people are over here industrializing the world and starting new things, while your people [meaning blacks and Latinos] are just taking up space.’”

A Violent Life Online

Cruz wore the Trump hat in a photo on an Instagram account the company said belonged to him. Over his face he wore a red, white, and blue bandanna. On that account and another one, Cruz posted photos of guns, knives, anti-Muslim slurs, and a picture of a toad he killed.

On YouTube, a person by the same name spewed hateful commentary about anti-fascists.

Cruz also celebrated Elliot Rodger, the gunman who killed seven people at the University of California, Santa Barbara in 2014 and who is considered a hero of the fringe men’s rights movement.

“Elliot rodger will not be forgotten,” Cruz commented on one video one year ago. He also commented on a CNN video called “Is our culture to blame for Elliot Rodger’s rants?”

The FBI said on Thursday it had received a warning from a YouTube user about a “nikolas cruz” who wrote in a comment, “I’m going to be a professional school shooter.” FBI field agents interviewed the tipsters, but the bureau’s special agent in charge in Parkland said the FBI was unable to identify the user.

Neighborhood Terror

Rhonda Roxburgh told The Daily Beast she had run-ins with Cruz when she lived with her parents, who were neighbors of the Cruz family.

One summer day in 2013, Cruz slammed his backpack into the rear door of Roxburgh’s car as she passed his house on her way to work. She stopped the vehicle and got out to confront the teenager.

“I said, ‘You can’t destroy people’s property. What were you doing?’” Roxburgh recalled. “He was snarky and laughing, and didn’t want to look at me.”

Later that day, Roxburgh knocked on his mother Lynda Cruz’s door and told her what had happened. “She said, ‘No, no, no. Not my Nikolas.’ She was pretty much in denial there was any issue with him at that point in time,” Roxburgh said.

As Roxburgh spoke to Lynda Cruz, Nikolas was walking through the yard and toward the street. She confronted him again on her way home.

“When he looked at me, that individual is a very, very cold, cold person. He did not care what I was talking about. He did not care what he did. I realized I was wasting my time with this child,” said Roxburgh, 45, who now lives in North Carolina.

Cruz was known to kill squirrels and birds with a pellet gun, and neighborhood cats would disappear, Roxburgh said. She said she once caught him jabbing a stick down a rabbit hole near his front yard.

At one point, Cruz walked his dog to a neighbor’s pen of piglets and tried to have the pooch attack them. “He was just a menacing child, to be quite frank,” said Roxburgh, who lived in the neighborhood from 2009 to 2015.

“If you knew he was killing animals, what else could he do? You got that sense that there was no emotion at all, unfortunately,” Roxburgh added. “Everyone was on the lookout for him. Everyone knew there was an issue.”

Roxburgh often saw Cruz and his brother, Zachary, together early on. In 2012, the siblings were the best of friends and were seen together in the street.

By 2014, the brothers “were definitely separate,” Roxburgh said. Nikolas would sit on the curb waiting for the bus, alone, with children 30 to 40 feet away from him.

“They would never really interact,” she said of the siblings. “Something happened there.” Zachary Cruz would ride his skateboard past his brother as he waited at the bus stop.

Meanwhile, Roxburgh said broken furniture—a damaged hutch, bookcase, and mattress—was often placed at the curb outside the Cruz family home. “I was thinking to myself, ‘They must not have any furniture left,’ because it was out there quite frequently,” she said.

Police were also called to the house often, Roxburgh said.

“Some of the other people in the neighborhood [said], ‘Boys will be boys.’ There was something else there, much darker than that,” Roxburgh said.

As for Cruz’s alleged right-wing link, Jereb claimed later on Thursday the media tricked him into identifying Cruz.

“It’s easy for them to misrepresent what I say. Are you really going to blame ME for the lying jew media?” he wrote on Gab, a social media site favored by the fringe right. Jereb did not reply to a further request for comment.

According to the Southern Poverty Law Center, more than 100 people have been killed or injured by perpetrators influenced by the alt-right since 2014.

Editor's Note, 2/15/18, 6:15 p.m.: This story has been updated throughout.

—Gideon Resnick and Elisha Brown contributed to this report