Polish authorities have arrested a man suspected of fatally shooting in broad daylight a Russian activist critical of President Vladimir Putin, authorities said Thursday.The suspect was a 36-year-old man who carried a passport belonging to the ex-Soviet republic of Georgia, Interior Minister Marcin Kierwiński said at a news conference in Warsaw.Robert Kuzovkov, known by the pseudonym Semyon Skrepetsky, was shot and killed at close range Monday near his home in the eastern Polish city of Biala Podlaska, a city near the border with Belarus.Polish Prime Minister Donald Tusk said Wednesday that the killing has the hallmarks of a political assassination.“Everything points to this being a political murder,” Tusk said. “But we must wait for evidence or more concrete indications. Because if that was the case — if it was ordered by Russia — then it is an extremely serious matter internationally. It would constitute state terrorism.”