By Andrew Osborn
Thousands of Russians have marched through Moscow to honour slain Kremlin critic Boris Nemtsov, the first anniversary of his death, and to press their demand that the authorities find and punish the person who ordered his killing.
The 55-year-old Nemtsov, an opposition leader and former deputy prime minister, was gunned down near the Kremlin walls late in the evening of February 27, 2015, as he walked home with his girlfriend from a restaurant.
Investigators have charged a group of Chechen men with his murder.
But Nemtsov's supporters say the suspects are just low-level operatives who were paid to kill the prominent critic of President Vladimir Putin.
They say the person who ordered the hit has been neither identified nor arrested.
"Nemtsov was killed because he had exposed Putin for what he was in various reports," one of the marchers, Irina Vorobyova, 60, told Reuters on Saturday.
"He was a worthy political opponent for Putin but he had insulted him."
Vorobyova, like many on the march, said she thought Ramzan Kadyrov, the Kremlin-backed leader of Chechnya, had ordered Nemtsov's murder to please Putin.
Kadyrov denies any involvement, though he has praised one of the suspects as "a true patriot of Russia".
The authorities locked down central Moscow for Saturday's event, sealing in the marchers with metal fencing guarded by police, some of whom wore body armour and helmets.
Police put the number of attendees at 7500 people, but one group of observers put it at 25,000. Some opposition figures said up to 100,000 people had turned up.
A Reuters reporter saw one man being dragged away into a side street in handcuffs.