A group of pro-Kremlin nationalist activists attacked two volunteers who were guarding a makeshift memorial on the Moscow bridge where former First Deputy Prime Minister Boris Nemtsov was shot dead.
On the night of September 7-8, about 10 activists from the East Radical Block (SERB) nationalist group sprayed pepper spray into the face of Grigory Samsonov and damaged a camera held by Pavel Kolesnikov at the memorial.
The attackers also threw feces at the men.
Kolesnikov told the OVD-Info rights-monitoring group that SERB leader Igor Beketov was among the attackers.
The vandals then stole flowers and portraits of Nemtsov and fled the scene.
Police did not arrive after the volunteers called and reported the incident.
Nemtsov, who was a leading opposition figure and an outspoken critic of President Vladimir Putin, was gunned down on the bridge near the Kremlin on February 27, 2015.
Five men from Russia's North Caucasus region of Chechnya were convicted of the murder, but it remains unknown who ordered Nemtsov's killing.
Authorities have refused to erect a memorial to the politician, so volunteers organized the makeshift monument near the place where he died.
Pro-Kremlin thugs have repeatedly attacked the volunteers who maintain a 24-hour guard at the site.
On August 15, 2017, an unknown assailant beat 35-year-old volunteer Ivan Skripnichenko. He died in the hospital on August 23 after undergoing surgery to repair damage to his nose.
In September 2017, SERB leader Beketov wrote on social media that his organization had removed a plaque honoring Nemtsov from the Moscow apartment building where he lived, less than one week after activists had erected it.