Portnov, 51, a former senior aide to Ukraine’s fugitive president Viktor Yanukovych, was killed in Madrid on May 21, 2025. Spanish media reported at the time that an unknown armed man shot him at the gates of the American School in Pozuelo de Alarcón, an upscale Madrid suburb.
Madrid police officers traveled to Gainsberg and, together with a German operations team, carried out the arrest, the statement said. Authorities said the suspect is believed to have been the shooter who killed Portnov outside a school in Madrid. The investigation is ongoing.
Police said a European arrest warrant and a European search warrant for the suspect’s residence had been issued earlier.
On May 28, 2025, Ukrainian media reported that Portnov met with
President Volodymyr Zelenskyy and his senior advisers during his May 17–19
visit to Kyiv.