The Justice Department has charged a man who squirted apple cider vinegar on Democratic U.S. Rep. Ilhan Omar at an event in Minneapolis, according to court papers made public Thursday.

The man arrested for Tuesday’s attack, Anthony Kazmierczak, faces a charge of forcibly assaulting, opposing, impeding and intimidating Omar, according to a complaint filed in federal court.

Authorities determined that the substance was water and apple cider vinegar, according to an affidavit. After Kazmierczak sprayed Omar with the liquid, he appeared to say, “She’s not resigning. You’re splitting Minnesotans apart,” the affidavit says. Authorities also say that Kazmierczak told a close associate several years ago that “somebody should kill” Omar, court documents say.

Kazmierczak has a criminal history and has made online posts supportive of Donald Trump, a Republican.