The suspect was detained by Poland’s Internal Security Agency (ABW).
The onet.pl website named him as Bartosz Kramek, the husband of Lyudmyla Kozlovska, head of the Poland-based Open Dialogue Foundation. It added that Kozlovska was expelled from Poland in 2018.
Kozlovska hit the news in August 2018 when Poland entered her in the European Union’s Schengen Information System (SIS) as a persona non grata, the tvp.info website previously reported.
Poland’s counterintelligence service said at the time that there were "serious doubts" about how her Open Dialogue Foundation was financed, according to tvp.info.
It added that “information gathered by the service indicated that the foundation's activities were supported by Russia, in whose interest it was to destabilize the political situation in many countries.”
However, some EU countries ignored the Polish alert and allowed Kozlovska to travel and stay on their territory, tvp.info said.