Suspect arrested after FBI uncovers alleged mass shooting plot

A Michigan suspect who authorities say expressed explicit neo-Nazi and antisemitic ideologies online was arrested Friday by the FBI who alleged he stockpiled weapons and was planning a mass shooting.

The United States Attorney's Office for the Western District of Michigan charged Seann Pietila, 19, of Pickford, Michigan with transmitting a communication containing a threat to injure another.

Investigators allege the suspect had communicated with another user on Instagram where they expressed strong views against the Jewish population, support for neo-Nazis and idolization of previous mass shooters, according to the criminal complaint.

When the FBI searched the suspect's home earlier Friday they found a cache of weapons, a Nazi flag, a ghillie suit, gas masks, and military sniper/survival manuals, the criminal complaint said.

A search of the suspect's phone found a message in the Notes app where he had identified a synagogue in East Lansing, a date and a list of equipment, according to the complaint.

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

Attorney information for the suspect wasn't immediately available.

The suspect's mother, Brittany Stob, told ABC News in a phone call on Saturday that her son is still in jail pending a detention hearing next week.

Stob asserted she believes her 19-year-old son is not violent and was not truly planning an attack, as alleged by federal prosecutors.

"He said some stuff online that he shouldn't have," Stob said. "He's a good kid. He would never hurt anybody."

Stob also said the guns and tactical gear seized by the FBI in the search of Pietila's home this week belonged to her and her husband, not her son.

Stob said her son began consuming antisemitic content online when he was isolated during the pandemic and didn't have access to the mental health treatment he needed.

The FBI said it received a report Tuesday about threatening communications made online, the complaint said. Meta provided investigators with information related to the user name associated with the threats and the FBI alleges it found several messages by the user, who was later identified as the suspect, making antisemitic slurs, and praising neo-Nazi ideology.

The suspect allegedly talked about his admiration for the 2019 Christchurch mass shooting in New Zealand, according to the criminal complaint. The date allegedly found on the notes app was the fifth anniversary of the New Zealand shooting.

Further investigation into the suspect's social media accounts found other images and posts that included posts of Nazi imagery and other mass shooters, the complaint said.

Among the contraband allegedly found in the suspect's home during the search warrant were magazines, a shotgun, a rifle, a pistol, various knives and firearms accessories, according to the complaint.

"No American should face threats against them based on their race or religion," James A. Tarasca, the Special Agent in Charge of the FBI in Michigan said in a statement. "Crimes like the one alleged in this complaint have a profound effect not only on the intended target, but on their entire community."