A Tunisian soccer player who was convicted of plotting a terrorist attack in Belgium and acquitted two decades later of similar charges in the United States is suing for his release, arguing that U.S. officials have illegally detained him for over a year in a private prison in Virginia after a jury in Washington found him not guilty.

Attorneys for Nizar Trabelsi, 54, said he has been confined in an immigration detention facility in Farmville, Va., as attorneys in immigration court wrangle over his next steps. He spends 23 hours a day in a windowless cell as his health deteriorates from conditions including anxiety, depression, post-traumatic stress disorder and diabetes, his lawyers said.

U.S. immigration officials are seeking to send Trabelsi to Tunisia, where he awaits a 20-year prison sentence after being convicted of terrorism without appearing in court and faces the possibility of torture, his attorneys said. They are asking a judge to release Trabelsi and facilitate his return to Belgium, as required by a U.S. extradition treaty with that country.

“As he fights off removal to Tunisia, Mr. Trabelsi is languishing … under conditions that are even more punitive and restrictive than the conditions he had to endure during his lengthy detention in pretrial custody as the United States attempted and failed to convict him of federal crimes,” according to the lawsuit, filed by Nicole Hallet of the University of Chicago Law School and Brett Kaufman, an ACLU attorney, in U.S. District Court in Alexandria.

Trabelsi’s lawsuit is the latest twist in a winding road that began with his arrest in Belgium two days after the 9/11 terrorist attacks, where he had moved after leaving his native Tunisia to be a professional soccer player who had first settled in Germany.

He testified at his trial in U.S. District Court in Washington last year that he met twice with Osama bin Laden while living in Afghanistan, but has maintained for years that he was convicted in Belgium based on a false confession he gave under duress.

Belgian police found an Uzi submachine gun in his apartment outside of Brussels and a list of chemicals used to manufacture explosives. His then-wife gave testimony played for jurors in the United States, recalling that Trabelsi told her he planned to commit a suicide bombing in Belgium or at the U.S. Embassy in Paris. (He has since remarried.) Trabelsi visited a restaurant where a co-conspirator in the Belgian case was stocking acetone and sulfur to produce a bomb, according to Belgian court records, although the attack never materialized. In 2007, after his conviction in Belgium, Trabelsi was sentenced for making death threats against a prison official in that country.

Trabelsi spent 10 years in prison in Belgium “for, among other things, having attempted to destroy the military base of Kleine-Brogel with explosives, having committed forgery, and having been the instigator of a criminal association formed for the purpose of attacking people and property,” according to a 2017 opinion by the U.S. Court of Appeals for the D.C. Circuit, which rejected claims that his extradition was illegal. U.S. forces are stationed at the Kleine-Brogel base in Belgium.

The federal jury in Washington found Trabelsi not guilty in July 2023 of charges including providing material support to al-Qaeda and conspiring to use weapons of mass destruction and to kill U.S. nationals outside the United States in the plot to attack the Belgian military base. He was then placed in the custody of U.S. Immigration and Customs Enforcement (ICE), which uses a contractor to run the detention facility in Farmville. Officials at the private prison have barred Trabelsi from having contact with his family and have kept him isolated, his attorneys said.

U.S. District Judge Randolph D. Moss, who presided over Trabelsi’s trial in Washington, said after the verdict that whatever happened to him in ICE custody would be outside his jurisdiction.

“After 22 years suffering in Belgium and here, I thought I would be free. Back to my family and normal life,” Trabelsi said in a statement provided by his attorneys. “I’ve been acquitted and I don’t know when I will be released. It’s torture. It’s endless.”

The Justice Department and ICE did not immediately respond to requests for comment.

The European Court of Human Rights has found that Trabelsi’s extradition was illegal, and Belgium has been asking U.S. officials to return him to that country, according to his attorneys. The human rights tribunal, based in Strasbourg, France, has ordered Belgium to pay Trabelsi $322,000 for violating his rights.

Rachel Weiner contributed to this report.