BERLIN (AP) — An employee of Germany’s foreign intelligence service and an acquaintance have been charged with treason for allegedly passing secret documents to Russia, prosecutors said Friday.

The intelligence officer, who has been identified only as Carsten L. in line with German privacy rules, was arrested in Berlin on Dec. 21 last year. The second suspect, a self-employed German businessman identified as Arthur E., was arrested at Munich airport on Jan. 22 as he arrived from the United States.

Germany’s Federal Intelligence Service, or BND, said at the time of the first arrest that it brought in prosecutors immediately after internal investigations substantiated information about a possible case of treason.

Federal prosecutors said Friday that Carsten L. had been acquainted with Arthur E. since May 2021, and that the latter was in contact with a Russia-based businessman with ties to the FSB, Russia’s domestic intelligence agency. The three allegedly met in September 2022 and conspired to procure sensitive BND information for the FSB.

Carsten L. supplied a total of nine documents related to a project on technical intelligence gathering on two occasions between mid-September and early October last year, printing them out or taking photos of them on his computer screen, prosecutors said in a statement.

He then gave the material to Arthur E., who photographed the printouts, took the digitized data to Moscow, printed it out and handed it to the FSB in meetings with Russian officers, they added.

In September 2022, an FSB officer gave Arthur E. a list of “questions of particular interest” and Carsten L. procured the answers, prosecutors said. They added that Carsten L. received at least 450,000 euros ($482,000) from the FSB and Arthur E. got at least 400,000 euros in cash, which the latter picked up in Moscow in November 2022.

After the cash pickup, Carsten L. arranged for Arthur E. to be “smuggled” past German customs after he landed for alleged professional reasons, according to prosecutors.

The two men were charged at a Berlin court with two counts of “joint perpetration of especially serious treason,” prosecutors said. They added that the information passed to the FSB was classified as state secrets.

Germany has become one of the leading suppliers of military and financial aid to Ukraine since Russia launched its full-scale invasion in February 2022.

In a previous case involving a suspected double agent at the agency, a former BND employee in 2016 was convicted of violating Germany’s official secrets law and sentenced to eight years in prison for providing classified information, largely to the CIA.