SILVER SPRING, Md. (AP) — A Maryland man charged in 2019 with planning an Islamic State-inspired attack at a Washington, D.C., area shopping and entertainment complex pleaded guilty on Monday to engaging in a separate plot to drive a stolen van into a crowd of people at a nearby airport.

Rondell Henry’s plea agreement with Justice Department prosecutors could lead to his release from federal custody as soon as October, when a judge is scheduled to sentence him in the airport plot, which Henry abandoned. Henry, who has remained in custody for over four years, didn’t harm anybody before police arrested him.

Henry, 32, of Germantown, Maryland, pleaded guilty to attempting to perform an act of violence at an international airport, court records show.

Henry admits that he stole a U-Haul van from a parking garage in Alexandria, Virginia, drove it to Dulles International Airport in Virginia and entered a terminal building on March 27, 2019.

“Henry unsuccessfully attempted to follow another individual into a restricted area of the airport, but the other individual prevented Henry from entering the restricted area,” according to a court filing accompanying his plea agreement.

Henry later told investigators that he went to the airport because he “was trying to hurt people there” and “was going to try to drive through a crowd of people,” but ultimately left because “there wasn’t a big enough crowd” at the airport, according to the filing.

Henry pleaded guilty to a felony that carries a maximum prison sentence of 20 years. But prosecutors and defense attorneys agreed that an appropriate sentence for Henry would be the jail time he already has served and lifetime supervised release with mandatory participation in a mental health treatment program, according to his plea agreement.

U.S. District Judge Paula Xinis, who isn’t bound by that recommendation, is scheduled to sentence Henry on Oct. 23. He will remain jailed until his sentencing hearing.

Henry’s attorneys didn’t immediately respond Monday to an email seeking comment on his guilty plea and plea deal.

Henry was charged in 2019 with attempting to provide material support to a foreign terrorist organization, the Islamic State group. But the charge to which he pleaded guilty is unrelated to what authorities had said was a ISIS-inspired plot to carry out an attack at National Harbor, a popular waterfront destination in Maryland just outside the nation’s capital.

Monday’s filing doesn’t mention the Islamic State or specify any ideological motivation for an attack at the airport.

Henry left the airport and drove the stolen U-Haul to National Harbor, where he parked it. Police arrested him the next morning after they found the van and saw Henry jump over a security fence.

Henry told investigators he planned to carry out an attack like one in which a driver ran over and killed dozens of people in Nice, France, in 2016, authorities said. A prosecutor has said Henry intended to kill as many “disbelievers” as possible.

Monday’s court filings don’t explain why Henry didn’t plead guilty to any charges related to the alleged National Harbor plot.

The case against Henry remained on hold for years amid questions about his mental competency. Last year, Rondell Henry’s attorneys notified the court that he intended to pursue an insanity defense.

Xinis had ruled in February 2020 that Henry was not competent to stand trial. She repeatedly extended his court-ordered hospitalization.

But the judge ruled in May 2022 that Henry had become mentally competent to stand trial, could understand the charges against him and was capable of assisting in his defense. Xinis said a March 2022 report on Henry’s medical condition found experts had restored his mental competence.

Prosecutors have said Henry watched Islamic State group propaganda videos of foreign terrorists beheading civilians and fighting overseas. Investigators said they recovered a phone Henry had discarded on a highway in an apparent attempt to conceal evidence, including images of the Islamic State flag, armed Islamic State fighters and the man who carried out the 2016 Pulse nightclub massacre in Orlando, Florida.

Henry is a naturalized U.S. citizen who moved to the country from Trinidad and Tobago more than a decade ago.