COLLEGE PARK, Md. (AP) — A psychologist who examined a man accused of planning an attack inspired by the Islamic State-group at a shopping and entertainment complex near Washington, D.C., found “ample evidence” that he is mentally unfit to assist in his defense, a court filing says.

Neither prosecutors nor a defense attorney for Rondell Henry plan to dispute the opinion that a court-appointed forensic psychologist from the Federal Bureau of Prisons detailed in a Dec. 20 report, according to Saturday’s court filing. The lawyers agree that Henry should be hospitalized at a Bureau of Prisons facility for up to four months to determine if it’s likely he will “attain the capacity to permit the proceedings to go forward,” the filing says.

A federal judge in Maryland didn’t immediately schedule a hearing on the matter.

Henry, 28, of Germantown, Maryland, was arrested on March 28, 2019, and is charged with attempting to provide material support to a foreign terrorist organization, the Islamic State group.

Henry is accused of stealing a U-Haul van in Virginia and parking it at the National Harbor, a popular waterfront destination just outside the nation's capital. 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. Henry intended to kill as many "disbelievers" as possible, a prosecutor from U.S. Attorney Robert Hur's office said during a hearing in April.

After his arrest by local law enforcement officers, Henry was taken for a psychiatric evaluation and held at a mental health facility for several days before FBI agents took him into custody.

Prosecutors didn’t object when Henry’s attorney, an assistant federal public defender, asked the court in September to order a psychiatric or psychological exam.

The psychologist who examined Henry determined that “there is ample evidence to indicate the defendant suffers from a mental disorder or disease that would substantially impair his ability to assist counsel in his defense.” The psychologist also recommended formal “competency restoration procedures” for Henry at a federal medical center.

Saturday’s court filing says Henry is traveling back to Maryland from an unspecified facility to be present for a hearing at which the psychologist will be available to testify by video conference.

Henry is a naturalized U.S. citizen who moved to the country from Trinidad and Tobago about a dozen years ago.

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 an Orlando, Florida.

The terrorism charge is punishable by a maximum sentence of 20 years in prison. Henry also faces a stolen vehicle charge that carries a maximum of 10 years in prison.