A prominent gun control advocate helped law enforcement track down and eventually arrest a Montana man on Monday after the suspect allegedly sent a wave of tweets threatening to kill Jews and open fire on children inside of a school.

David Joseph Lenio of Kalispell, Mont. was charged with intimidation and criminal defamation for his alleged threats to “execute #grade #school kids” and “shoot up a synagogue,” The Flathead Beacon reported on Thursday.

He also reportedly tweeted that the best way to “handle” Jews was to repeat shootings such as a recent one in Chapel Hill, North Carolina, in which a white man has been accused of killing three Muslim American students.

His roommate told Kalispell police that Lenio had moved several guns and ammunition from a storage locker into their apartment only a day before the arrest, according to the newspaper.

Officers later searched the apartment and vehicle and found a handgun, a bolt action rifle and a semi-automatic rifle, the paper reported. Police also reportedly found ammunition, a pipe, and jugs of urine.

Jonathan Hutson, the chief spokesman for the Brady Campaign to Prevent Gun Violence, appears to have been a key to leading authorities to Lenio by providing the FBI and police several of the man’s Twitter handles on Feb. 14.

Hutson told TPM in an interview on Friday that he began monitoring Lenio’s accounts after the man responded to one of his tweets, a post linking to a New York Times article about the shooting in Copenhagen, in which a Jewish man was killed.

“He tweeted at me,” Hutson told TPM on Friday. “It just happened that, of all the people with whom he could’ve tangled, he chose a spokesperson for the Brady Campaign who had a background as an investigative reporter.”

Hutson was ready to dismiss Lenio as a “garden variety Internet troll” until the suspect began tweeting what he interpreted as threats, such as an image of a noose.

“He tweeted to me and asked where my kids went to school,” Hutson said. “So that made me go into dad grizzly mode and stay up all night to help law enforcement find this guy.”

Once Hutson scrolled through Lenio’s Twitter feed and found it packed, he said, with direct threats to kill schoolchildren and Jewish people, he decided he had enough evidence to notify the authorities.

Hutson initially called the Oregon FBI and Linn County Sheriff’s Office since Lenio’s Twitter profile hinted at an old address from that state.

Hutson said Linn County authorities tracked Lenio’s IP address and found him in Montana and also spoke to the suspect’s father, who said he believed his son was mentally ill.

Lenio’s alleged tweets, provided to TPM by Hutson, were rife with anti-Semitism and conspiracy mongering, as well as discussions of guns, his employment troubles and his own mental health issues.

“Best way to counter the harm #jewish #politics is causing is #ChapelHillShooting styling [sic] killing of #jews til they get the hint & leave,” Lenio tweeted on Feb. 13.

Another, from Feb. 12: “USA needs a Hitler to rise to power and fix our #economy and i’m about ready to give my life to the cause or just shoot a bunch of #kikes…”

More than a dozen tweets provided by Hutson also appeared to threaten to open fire in a school.

“I bet I’d take out at least a whole #classroom & score 30+ if I put my mind to it,” he tweeted on Valentine’s Day. “#Poverty is making me want to kill folks #MentalHealth?”

Another: “I bet I could get at least 12 unarmed sitting ducks if I decide to go on a killing spree in a school. Sounds better than being a wage slave.”

Lenio also appeared to have published about 70 videos on YouTube under the alias “David Dave,” in which he recorded more theories about gun rights, Jewish-controlled government, and “false flag” mass shootings and bombings (such as the Sandy Hook Elementary School shooting in Connecticut, which Lenio referred to as “Sandy Hoax”).

In one of the videos, according to the Southern Poverty Law Center, Lenio waved a .32-caliber Caltech semi-automatic handgun on camera. He also recorded slam poetry and a video supporting “Ron Paul 2012.”

In a court appearance on Thursday, Lenio shouted out “free Palestine” and told onlookers to visit his YouTube page and learn the “truth” about the 9/11 attacks and the 2011 shooting of former Rep. Gabrielle Giffords (D-AZ), according to the Beacon.

Lenio faces up to 20 years in prison and fines up to $50,000, the Beacon reported.

Two of his Twitter accounts, @PsychicDogTalks and @PyschicDogTalks2 [sic] have been suspended by Twitter for violating its terms of service, but @PsychicDogTalks3, created after his initial threats to Hutson, remains online.

His Twitter followers, and those he followed, included many white supremacist accounts. Here are screengrabs of the tweets provided to TPM by Hutson: