Russian artist and Kremlin critic Semyon Skrepetsky was shot dead Monday morning in Poland, officials said, in a killing that has shocked opposition activists and raised questions about whether his political work played a role in his death.

Prosecutors identified the victim as 44-year-old Robert Kuzovkov, better known by his artistic name, Semyon Skrepetsky. He had been living in Poland since leaving Russia several years ago and was known for performances and artwork attacking Vladimir Putin and other authoritarian leaders.

The shooting happened shortly before 10 a.m. in a residential area of the eastern Polish city of Biała Podlaska. According to investigators, a man approached Skrepetsky on a pedestrian path and opened fire. Three shots were fired first, they said. After Skrepetsky fell to the ground, the attacker reportedly walked closer and fired two more times.

A preliminary examination found five gunshot wounds, including injuries to the chest and head. Investigators have not publicly described the attack as an execution, but the details released so far suggest the gunman wanted to make sure the victim was dead.

The killer escaped and has not been found.

Police launched a large search operation after the shooting, setting up checkpoints and looking for witnesses. Officers have secured surveillance footage and collected forensic evidence from the scene, prosecutors said.

On Tuesday, authorities confirmed that two Belarusian citizens had been detained near the Belarusian consulate in Biała Podlaska. Prosecutors stressed that the men have not been charged and that investigators are still trying to determine whether they have any connection to the killing.

Skrepetsky left Russia in 2021 saying he feared political persecution. After arriving in Poland, he continued creating anti-Kremlin artwork and public performances. His targets included Putin, Belarusian leader Alexander Lukashenko and Chechen leader Ramzan Kadyrov.

Just days before his death, he staged a protest in Berlin in front of the Russian embassy. One of the works he displayed linked modern Russia's leadership to the Soviet past. Images from the performance spread online and drew attention within Russian opposition circles.

According to Polish media reports, friends and supporters have said Skrepetsky received threats because of his activism. Investigators have not confirmed any link between those threats and the shooting, but they have not ruled out a political motive.