The imprisonment of Guatemalan investigative journalist José Rubén Zamora was found to be “arbitrary” and in violation of international law by a human rights body investigating cases of deprivation of liberty at the United Nations.

In a decision made public on Monday, the United Nations’ Working Group on Arbitrary Detention concluded that Zamora’s arrest on July 2022 for alleged financial crimes was the result of his “legitimate exercise of the right to freedom of expression.”

As the founder of the renowned independent investigative newspaper “elPeriódico,” Zamora oversaw dozens of investigations into corruption since it was founded in 1996 — making him and his family vulnerable to government-run defamation campaigns, car explosions, illegal raids, kidnappings, death threats and assassination attempts.

At the time of Zamora’s arrest, the newspaper had published stories pointing to 144 cases of corruption during the administration of then-President Eduardo Giammattei.

Some of the most notorious involved corruption in the purchase of Covid-19 vaccines and bribery of Guatemalan officials doing business with Russian miners, according to Zamora’s son, José Carlos Zamora Marroquín.

Zamora Marroquín recalled that the attacks against his father intensified following the investigations. The newspaper was forced to shut down last year, he said.

Last year, Zamora was sentenced to six years in prison for money laundering. Numerous human rights organizations have said Zamora’s trial proceedings were riddled with failures — including violations of due process, misuse of pretrial detention and obstruction of his right to legal defense.

“The Working Group considers that, taking into account all the circumstances of the case, the appropriate remedy would be to release Mr. Zamora immediately and to grant him the effective right to obtain compensation and other forms of reparation,” the decision reads in Spanish.

The decision was issued in response to a complaint filed by The Vance Center in August, arguing that Zamora’s continued imprisonment met the definition of arbitrary detention.

The Vance Center has represented Zamora since 2022, assisted by a team of pro bono lawyers from King & Spalding and the Chilean law firm of Ciro Colombara.

According to Wilmer González, a program adviser at The Vance Center, this is the first time that the U.N.’s working group has determined that detaining someone for their political stance against corruption constitutes an arbitrary detention.

“This landmark opinion is important not only for José Ruben Zamora’s case, but also because it establishes a legal precedent,” González said in a statement Tuesday.

‘This decision clearly spells out what the Guatemalan government must do next: release Zamora immediately and take necessary steps to remedy the violations of his rights,” González said.

This article was originally published on NBCNews.com