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Image of Matthew Althorpe from an agreed statement of facts for guilty plea and sentencing document. HO/Ontario Superior Court of Justice

An Ontario man who was a member of a now-defunct neo-Nazi group, Atomwaffen Division, pleaded guilty on Thursday to terrorism charges, admitting to producing white-supremacist propaganda that prosecutors say may have inspired several deadly attacks around the world.

Matthew Althorpe is one of several Canadian members of the designated terrorist group who has been convicted in Ontario’s courts in recent months.

Mr. Althorpe pleaded guilty to terrorism charges and agreed to a 34-page statement of facts entered into evidence in a Toronto court by prosecutors on Thursday.

The agreed statement of facts says that Mr. Althorpe served as a propagandist for the Atomwaffen and several of its offshoots for several years starting in 2018. Following its unravelling in 2020, he played a leading role in other violent groups – including an online incitement hub known as Terrorgram and later, a Southwestern Ontario chapter of a fighting group called Active Club.

Prosecutor Amber Pashuk told court that Mr. Althorpe co-wrote and helped distribute incendiary neo-Nazi manifestos that were read and referenced by terrorists elsewhere, including ones involved in attacks against Muslims, gays and lesbians, as well as ones plotting strikes against critical infrastructure.

“Terrorgram publications have been cited in manifestos published by terrorists in the U.S., Europe, South America at the time of their attacks,” Ms. Pashuk said. She said some of the known attacks included a 2022 shooting that killed two people in a gay bar in Bratislava, Slovakia; a 2024 plot by a New Jersey man to take out an electric substation; and a mass stabbing at a mosque in Turkey that wounded five people.

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Mr. Althorpe, who was charged in December, 2023, pleaded guilty to three of eight criminal charges he had been facing, including participating in terrorist activity, instructing others to carry out terrorist activity, and committing offences for a terrorist group by encouraging hatred against Jews, Muslims, Blacks, and gays and lesbians, among other groups.

Prosecutors told the court Mr. Althorpe amplified the ideology of the Atomwaffen, a group which told its adherents that white ethno-states would be created if enough people engaged in acts of terrorism that accelerated a society-ending race war.

Court heard that Mr. Althorpe was part of a militant online subculture that encouraged people to attack synagogues, kill police, and attack electrical systems at the height of summer so people would die of heatstroke.

He could have faced more than 30 years in prison if he was convicted on all eight terrorism counts, prosecutors said. But because he pleaded guilty, he will now face up to 20 years in prison. Mr. Althorpe’s lawyer, Robb MacDonald, is advocating for a sentence of less than 14 years.

Sentencing is anticipated later this fall. The next court date is scheduled for Nov. 5.

A co-accused in the Toronto case is contesting the terrorism charges that he faces. Court heard Thursday that Kristoffer Nippak has elected to appear before a judge-alone trial in the coming months.

In court on Thursday, the agreed statement of facts read by prosecutors detailed the content of several online videos and manifestos that Mr. Althorpe participated in making and distributing.

The videos showed Atomwaffen members in black skull masks congregating in the woods in Ontario and Quebec, firing rifles and burning books. The footage is juxtaposed with text flashing across the screens, including swastikas and messages imploring viewers to “Join us” and “Purge the weak.”

Members have been targeted by a series of escalating law-enforcement actions by federal government officials in recent years.

In early 2021, the Atomwaffen was designated as a terrorist entity by Public Safety Canada.

In August, a Windsor man named Seth Bertrand was found guilty of contributing to a terrorist group after filling out an online application form to try to formally join the Atomwaffen. He has not yet been sentenced.

The ruling in that case said Mr. Bertrand drew swastikas on the WE Trans Support building in Windsor and engaged in other acts of vandalism in a bid to bolster his membership application. In his online communications, he quoted Adolf Hitler and pledged his loyalty to the group and its white-supremacist cause.

In an Ottawa court in September, another propagandist for the group received a 10-year jail sentence after being convicted of terrorism activities for the Atomwaffen group.

Patrick MacDonald, who operated under the online moniker “Dark Foreigner,” also participated in the creation of the propaganda and recruitment videos showing up to 10 individuals at a time wearing skull masks, battle fatigues and black jackboots, marching and firing automatic weapons.