DES MOINES, Iowa (AP) — The superintendent of Iowa’s largest school district, who was detained last week by immigration agents, was charged Thursday in federal court with possessing firearms while in the U.S. illegally, prosecutors said.

Ian Roberts resigned this week as Des Moines’ superintendent of schools, just days after he was pulled over and fled from U.S. Immigration and Customs Enforcement agents, who ultimately arrested him with the help of officers from the Iowa State Patrol. When he was arrested, federal agents found a handgun that was wrapped in a towel inside the Jeep Cherokee he was driving, according to court papers.

Roberts, who is originally from Guyana, had been jailed in Sioux City, about 150 miles (240 kilometers) northwest of Des Moines, since late Friday afternoon. Officials said he was taken into custody on a federal arrest warrant for the weapons charge and appeared by video before a federal magistrate judge.

Roberts’ attorney, Alfredo Parrish, said his client will plead not guilty.

“Our position at this time — he has a presumption of innocence,” Parrish said. “He will exercise his right to indicate to the court, if he is indicted, that he’s not guilty,” Parrish said, adding that there has not been an indictment returned by the grand jury.

Roberts, 54, is alleged to have been in possession of four firearms, according to court documents. Authorities said Roberts had been authorized to work in the U.S. between December 2018 and 2020 but has since “not had lawful employment authorization,” according to the complaint.

Federal authorities said Roberts had a final removal order that was issued last year, and an immigration judge denied a motion to reopen Roberts’ immigration case in April this year. The complaint released Tuesday alleged that Roberts had that final removal order in a different car at his residence.

Roberts had been under the impression from a prior attorney that his immigration case was “resolved successfully,” his attorney has said.

“It has been my pleasure to represent you throughout this process, and I am pleased to report that your case has reached a successful resolution,” Texas attorney Jackeline Gonzalez wrote on March 27.

An aide to Gonzalez confirmed to The Associated Press Tuesday that the law firm had represented Roberts but gave no immediate comment.

Gonzalez spoke earlier this week to federal officials and said the letter she sent had informed Roberts “that the immigration case with Gonzalez’s office was being closed,” according to court papers. Roberts had an unpaid legal bill with her office.

“Gonzalez added that the letter was not intended to convey” that his case with the court had been completed, the court documents said.

Gonzalez declined to tell authorities, however, about her communication with Roberts about the immigration judge’s denial of the motion to reopen his case, which was sent to her office.

One firearm, the one found under the driver’s seat of his school-issued vehicle when he was arrested, was a pistol believed to have been purchased by Roberts’ wife, authorities said. The other three — a pistol, a rifle and a shotgun — were found during a search of Roberts’ home, the complaint said, and all were allegedly loaded.