After two years of admiring and studying the Islamic State fighters who beheaded and attacked civilians abroad, the government asserts, Rondell Henry decided it was time to join the ranks of the terrorists he considered “brave.”

The Maryland man started spending more time with his family, thinking he would never see them again, prosecutors said. He told his landlord March 24 that he was breaking his lease, and two days later, he walked off his job in the middle of a shift, the government said.

Henry turned away from the life he had spent building for himself in the United States over a decade with the intention of “killing as many disbelievers as possible” in a suicide attack, prosecutors said.

But the plot he’s accused of was quickly uncovered. Federal and local law enforcement in Maryland said what started out as investigations into a missing person — Henry — and a stolen U-Haul van turned out to be the thwarting of a terrorist attack targeting families and civilians at a major international airport and a busy waterfront entertainment destination outside of Washington.

A federal magistrate judge on Tuesday ordered Henry, 28, of Germantown to remain in jail pending trial in what the government called an Islamic State-
inspired plot.

Michael CitaraManis, an assistant federal public defender representing Henry in the federal case, said Henry has no prior criminal record and urged the judge to view the government’s assertions with suspicion.

Henry appeared in U.S. District Court in Greenbelt, Md., one day after the government publicly accused him of plotting to mow down crowds with a stolen van to “commit mass murder.”

Federal authorities have charged him with taking a stolen car across state lines, but he is not charged with a terror-related count. No additional charges were entered Tuesday.

In court, prosecutors echoed the accusations made in earlier court filings that in March, Henry sized up Dulles International Airport for two hours to see if it had a large enough crowd for his plot. Finding too few people there, they contend, Henry drove to another target — busy National Harbor in Prince George’s — with the same notion to run down pedestrians with the van.

“The only evidence the government has to submit is what they claim Mr. Henry” told law enforcement, said CitaraManis, who said Henry’s rights were violated while being questioned by authorities. “We don’t know exactly everything Mr. Henry said.”

Federal prosecutors say Henry’s plans began to unfold on March 26, when he walked off his job and prepared to launch a truck attack similar to one in Nice, France, that killed 84.

Henry tailed a U-Haul to a mall in Alexandria, Va., where he stole the van from a parking garage on March 26, prosecutors say. The next morning about 5, he arrived at DullesAirport, parked, andtried to access restricted areasand “obtain paperwork from a check-in kiosk.”

Officials at the Metropolitan Washington Airports Authority declined Tuesday to detail Henry’s whereabouts while at the airport. They would not say where Henry’s van was parked during the time he is said to have spent there and said they are cooperating with investigators.

Unsuccessful at Dulles, Henry drove to National Harbor to get “the largest number of casualties,” Assistant U.S. Attorney Thomas P. Windom saidin court Tuesday.

“He wanted bloodshed, he wanted chaos, he wanted panic,” Windom said.

Henry then broke into a nearby boat — named the “Govanish” — where he hid overnight to wait for the right time to launch his plot, federal prosecutors and local charging documents state.

On March 28, police spotted Henry leaping over a security fence from the boat dock and arrested him, court documents state.

Prince George’s County policearrested him for the suspected boat break-in and subsequently learned of his alleged plan.

“This defendant appears to have formed a plot to harm large numbers of people and taken concrete steps to execute that plot,” Robert K. Hur, the U.S. attorney for Maryland, said during a news conference after the hearing.

Prosecutors said Tuesday that Henry laid out his plan in videotaped statements to authorities.

“This case emphasizes our greatest threat right now is homegrown violent extremists,” Jennifer L. Moore, the acting FBI special agent in charge for the Baltimore field office, said Tuesday.

Henry, who prosecutors said was born in Trinidad and Tobago and is a naturalized U.S. citizen, did not enter a plea to the federal charge. He wore a maroon jail jumpsuit during proceedings, and his family members sat toward the back of the courtroom.

His relatives and attorney declined to comment outside court.

CitaraManis said his client’s rights had been violated and that the government took extreme steps to keep him from an attorney and his family.

Though Henry has no history of mental illness, CitaraManis said, authorities hospitalized Henry briefly after his March arrest for an emergency psychiatric evaluation. Henry was at the hospital for six days before he was released on April 3 and picked up by the FBI, his lawyer said.

After Henry walked out of his job, Montgomery County police reported Henry as a “critical missing person.” The March 27 lookout said his family had been unable to contact him, and he was last seen by co-workers around noon the day before “when he left his place of employment in Germantown.” Capt. Tom Jordan, a Montgomery County Police spokesman, said Tuesday that Henry’s family members had reported him missing.

Thomas Mooney, an attorney for Henry on the breaking-and-entering charges filed in Prince George’s County, said Henry has not been presented before a judge in state court, but he intends to enter a plea of not guilty.

A spokeswoman for Germantown-based Hughes Network Systems said that Henry formerly worked at the company as an independent contractor on the internal help desk of its IT department. A spokeswoman Tuesday did not offer any additional details, including about when Henry was employed there.

A neighbor of Henry’s, Shea Foley, said Monday that he met Henry in 2017 when Foley moved into a unit directly below Henry’s in their three-story apartment building.

Foley said there was often noise during the night from Henry’s apartment from what Foley said were people walking around until 4 a.m. or 5 a.m.

Henry agreed to cut down the noise after Foley brought it up to him, but Henry seemed private and wanted to keep to himself.

A third-floor neighbor, Meydin Osorio, recalled Monday that days earlier she and her 17-year-old son heard a commotion and banging outside their door.

“Who is it?” her son had asked on Friday amid the noise, his mother recalled.

“FBI. It’s not for you. Sorry. Stay inside,” the people with “FBI” written on their vests in the hallway said, Osorio recalled.

Osorio said she met Henry a short time after she moved into the building about three months ago. She was walking down her stairs about 6 a.m. to get to work one morning as Henry walked in, she said, and she smiled and said “Good morning.” He gave the slightest smile, she said, and the slightest nod, but he did not say anything.

Jennifer Jenkins and Lori Aratani contributed to this report.