The District Court in Białystok, eastern Poland, delivered the verdict on January 9, though it was only made public on Monday.
The 43-year-old man, identified only as Saulius V. under Polish privacy laws, accepted the sentence without a trial, making the judgment final, Polish state news agency PAP reported.
Jacek Dobrzyński, spokesman for the government minister overseeing Poland's security services, said investigators from the Internal Security Agency (ABW) had gathered evidence indicating that the Lithuanian, claiming to be an active officer of the US Central Intelligence Agency (CIA), had declared his willingness to provide information to the Belarusian State Security Committee between November 2024 and March 2025.
The court found him guilty of an attempt to offer assistance to a foreign intelligence service against NATO allies Poland and the United States, authorities said.
Under Polish law, the offence carries a prison sentence of six months to eight years.
According to Dobrzyński, the man had "employed sophisticated technical means in his activities," including artificial intelligence tools.
Saulius V. was arrested on March 14, 2025 by ABW officers.
The investigation was conducted by the Białystok branch of the Internal Security Agency under the supervision of the local division of the National Public Prosecutor’s Office.
From the time of his arrest until sentencing, he was held in custody, which the court credited towards his one-year sentence.
(mp)
Source: PAP/X/@JacekDobrzynski/ABW