Polish authorities arrested three people on Friday in relation to the attack on an ally of the late Russian dissident Alexei Navalny. Leonid Volkov was “brutally attacked” in mid-March outside his home in Lithuania, where he lives in exile.

The arrests were announced by Polish Prime Minister, Donald Tusk, who released a statement on X (Formerly Twitter). Two Polish individuals and one Belarusian, who is suspected to have orchestrated the attack, were arrested and are now in custody. He further stated that the detained individuals are associated with extremist groups and assured that there would be no leniency for anyone who collaborates with Russian services.

The President of Lithuania, Gitanas Nauseda welcomed the news, praising law enforcement’s efforts and stating he was “glad to announce the suspects had been detained.” He further stated: “Together we warn the organizers of the crime: do not try to repeat it!”

Volkov was attacked on March 12 outside his home in Vilnius. The attackers reportedly smashed his car window, sprayed Volkov with tear gas and hit him fifteen times with a hammer. He was briefly hospitalized after the attack. Volkov spoke out on social media following the arrest of the suspects in a statement responding to Nauseda:

Thanks a lot, Mr. President. And great thanks to Lithuanian and Polish law enforcement agencies for the tremendous work they’ve done. It is of enormous importance to investigate and to expose all the chain-of-command from Putin to the guy with the hammer.

Volkov was a long-term ally and chief of staff to Navalny, who died in prison in February while serving a nineteen-year sentence. Volkov faces many charges that he says are politically motivated.