The FBI has arrested a man in Michigan who allegedly posted threats online that he would carry out a mass shooting against conservative Christians if former President Donald Trump won the 2024 election, according to recently unsealed charging documents.

Isaac Sissel was taken into custody in Canton, Michigan yesterday, just two days after law enforcement reviewed his online post.

The criminal complaint states that Reddit reported Sissel to the FBI in late September for various accounts with threatening usernames, including “ShootUpTrulyRally,” “WillShootTrumpSoon,” “PlannigToShootTrump” and “PlanningToKillTrump.”

Law enforcement contacted Sissel at a Travelodge hotel in Canton yesterday and found no weapons during an authorized search of his room. However, the affidavit states, “This was not surprising since SISSEL stated (in his online post) that he 'hid the gun.'”

Sissel further told agents that Trump was “a threat … who should have been assassinated and that everything would be better if Trump were dead,” the affidavit states. Although he said he wouldn't personally assassinate Trump, he told agents he believed there would be violence during the election “and wouldn't rule out joining Antifa to protest.”

According to the affidavit, Sissel is a transient who has recently lived on the University of Michigan campus and has multiple warrants for his arrest for stalking, harassment and harassing communications.

The arrest underscores the FBI's aggressive response to counter a wave of violent threats related to the presidential election, particularly after the two assassination attempts against Trump. In the affidavit, the FBI specifically referenced Trump's plans to appear at a rally in Michigan late Monday.

According to his court records, Sissel has not been charged or entered a plea as of Tuesday afternoon. He has not yet been assigned an attorney.

-Alexander Mallin from ABC News