The Long Island man allegedly behind a series of threats where he described wanting to "shoot up" a Manhattan synagogue admitting to being part of an online white supremacist group, prosecutors said in court documents.
Law enforcement officials declared Saturday the arrests of two New York men at Penn Station prevented a "developing threat" to the Jewish community.
Christopher Brown and Matthew Mahrer were stopped at the bustling transit hub late Friday, hours after Brown had been identified by authorities for allegedly posting a series of threats on Twitter. The pair were in possession of numerous weapons, police said.
"Two MTA police officers assigned to patrol at Penn Station late Friday night, having been notified by an MTA PD detective assigned to the FBI/NYPD Joint Terrorism Task Force (JTTF), identified two men wanted in connection with threats to the Jewish community," MTA Police Department Chief John Mueller said in a statement.
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In addition to a "military style knife" in their possession, authorities said a firearm and high capacity magazine were recovered from Mahrer's Upper West Side apartment building.
Brown, of Aquebogue, faced a judge on Sunday for charges of weapon possession and making a terroristic threat. Charging documents include some of the violent tweets published in the last week; one claimed Brown was "gonna ask a priest if I should become a husband or shoot up a synagogue and die."
A week before his arrest the 21-year-old allegedly tweeted, "big moves being made on Friday."
In addition to the multiple weapons recovered in their arrest, prosecutors also said Brown was in possession of a swastika armband, ski mask and bulletproof vest. Specific details of any plan he may have intended to carry out have not been released by officials.
The court documents detail a statement Brown made to authorities on Saturday in which he admitted to purchasing a firearm with Mahrer from a friend in Pennsylvania. He also allegedly claimed responsibility for posting the threatening tweets and said he belonged to a white supremacist Twitter group.
An email to Brown's public defender was not immediately returned Sunday morning.
"A potential tragedy was averted when they were intercepted by police officers at Penn Station, given that online postings indicated an intent to use these weapons at a Manhattan synagogue,” Manhattan District Attorney Alvin Bragg said.
The Anti-Defamation League said its organization first identified the online threats in Brown's closed Twitter account and found hundreds of antisemitic tweets posted in the past week.
"This is a person who was very active on social media and that's part of the reason why law enforcement was concerned about him," Scott Richman, regional director of the ADL, told News 4.
Mahrer, who has only been charged for weapon possession, was arraigned late Saturday and remanded without bail. His attorney argued in court that the 22-year-old had no criminal history and said he’s of “Jewish heritage," the NY Post reported.
The head of the NYPD said police commanders would be "strategically deploying assets at sensitive locations throughout New York City" in the wake of the arrests.