FBI agents on Friday arrested a man in Michigan suspected of planning a deadly assault at a local synagogue.

According to US federal court filings, Seann Patrick Pietila regularly made antisemitic comments on Instagram and also expressed support for a pair of right-wing extremists convicted of mass killings in Norway and New Zealand which together left over 120 dead.

The documents said that a search of his phone revealed a note listing Congregation Shaarey Zedek and the date March 15, 2024, which apparently referred to the 2019 Christchurch mosque shootings in which 51 were killed. The note had a list of equipment that included guns and explosives.

Investigators also found a number of weapons and a Nazi flag during a search of his home in Pickford.

Pietila, 19, was charged with transmitting a communication that contained a threat to injure someone. He made an initial court appearance Friday and is set to attend another hearing next week.

“Antisemitic threats and violence against our Jewish communities – or any other group for that matter – will not be tolerated,” Mark Totten, the US attorney for the Western District of Michigan, said in a statement. “Today and every day we take all credible threats seriously.”

The arrest came the same day as a court convicted the perpetrator of the 2018 Pittsburgh synagogue massacre, in which 11 congregants were killed in the deadliest attack on Jews in US history.