Editor's Note: This article originally appeared on Business Insider.

Paul Whelan, the former US Marine accused of espionage, has been sentenced to 16 years in a high-security Russian prison.

A judge in Moscow handed down the sentence on Monday.

Whelan, 50, was arrested in a luxury Moscow hotel on December 28, 2018, and formally charged with espionage a week later. He has been in pre-trial detention since.

Russia's security agency, the FSB, said at the time he was detained “while on a spy mission.” Whelan's family has rejected that charge and said he was in town to attend a wedding of a fellow Marine veteran to a Russian woman.

Russia said Whelan was caught with a USB drive containing classified information. Whelan said he was set up and thought the flash drive, which was given to him by a Russian acquaintance, contained holiday photos.

He previously told the BBC the acquaintance had showed up to his room uninvited and placed the drive there.

The US has repeatedly said there is no evidence against him.

According to The Washington Post, Whelan on Monday shouted in the court room that the case was a “political charade,” and that Russia was taking political prisoners because it “feels impotent in the world.”

Inside his glass defendants' box he also held up a piece of paper calling the trial a “sham trial” and a “meatball surgery.”

He also said he didn't understand any of his judicial proceedings because they were in Russian, The New York Times reported. His lawyer, Vladimir Zherebenkov, plans to appeal, both newspapers said.

US Ambassador to Russia John Sullivan on Monday called Whelan's imprisonment a “mockery of justice” and “an egregious violation of human rights and international legal norms.”

Whelan's 2018 detention came two weeks after Maria Butina, a Russian gun-rights activist based in the US, pleaded guilty to engaging in a conspiracy against the US.

Butina pleaded guilty to working with a Russian government official to establish informal “back channel” communications with the US government via the National Rifle Association.

Experts at the time said Whelan's detention may have been linked to Butina's arrest. Bill Browder, the British financier behind the Magnitsky Act, said at the time that Whelan's arrest “looks increasingly like a hostage situation.”

She was imprisoned in the US in April 2019, and let out in October that year. She has since returned to Russia.

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