GREENBELT, Md. (WJZ) — A Maryland man accused of planning an Islamic State-inspired attack at a shopping and entertainment complex near Washington, D.C., pleaded not guilty on Monday to a federal criminal charge.

Rondell Henry, 28, of Germantown, allegedly spent the past two years studying and admiring ISIS members who carried out terror attacks. Prosecutors said he plotted his own, targeting National Harbor, planning to use a stolen U-Haul truck to run people down.

According to an April 9 statement by Maryland U.S. Attorney Robert Hur, “based on our investigation so far, this defendant appears to have formed a plot to harm large numbers of innocent people and taken concrete steps to execute that plot.”

The alleged plot was based on the truck attack in France in 2016, which killed dozens. In federal court in Greenbelt, Henry entered a not guilty plea at his Monday morning arraignment.

Born in Trinidad, he moved to the U.S. ten years ago and is a naturalized citizen. Investigators say he broke into a boat at the National Harbor to sleep and was spotted by police and arrested.

Again on April 9th FBI acting special agent Jennifer Moore said “this case emphasizes our greatest threat right now are homegrown violent extremists. These individuals who radicalize independently and alone in their own home with little to no warning.”

A trial date will be set May 21st. When it starts, it’s expected to last six days.

He was indicted April 10 on the charge, which carries a maximum sentence of 10 years in prison.

In a court filing, prosecutors said Henry watched Islamic State propaganda videos of foreign terrorists beheading civilians and fighting overseas, admiring their actions and considering them brave. Investigators said they recovered a phone Henry 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 Pulse nightclub massacre in an Orlando, Florida.

Henry initially considered an attack at Dulles International Airport on March 27, trying unsuccessfully over two hours to breach the security perimeter by slipping in through a checkpoint or accessing a restricted area, prosecutors said. Instead, he drove to the National Harbor later that morning, parked the truck, broke into a boat and hid there overnight, according to prosecutors.

Some Associated Press coverage was used in this story.