The prosecution has concluded the presentation of its case in the Moscow trial of U.S. citizen Paul Whelan on espionage charges that he denies.

Whelan’s lawyer, Vladimir Zherebenkov, told Russian state media on April 27 that “the evidence for the prosecution is unconvincing.”

He added that Russian security services had been paying attention to Whelan for “several years prior to his detention” and that the case bore “signs of a provocation.”

Whelan, who also holds British, Canadian, and Irish citizenship, was arrested in Moscow in December 2018. Prosecutors claim that a flash disc in his possession contained classified information. He faces up to 20 years in prison if convicted.

Whelan, 50, denies the allegations against him, calling them political in nature, and has alleged being mistreated by guards. The former U.S. marine has said he traveled to Moscow to attend a wedding.

The trial in the Moscow City Court is being held behind closed doors because the evidence includes classified materials and because of measures taken to slow the spread of the coronavirus.

The trial is scheduled to resume on May 13 with defense questioning of witnesses.

Based on reporting by Interfax, TASS, and The Washington Post