Natalia Estemirova's mother (with handkerchief) and daughter (in light T-shirt) attended her funeral in rural Chechnya
Russian President Dmitry Medvedev has paid tribute to human rights activist Natalia Estemirova, whose murder has caused international concern.
Speaking in Germany, as her funeral was being held in Chechnya, he promised a thorough investigation and pledged those responsible would be caught.
Ms Estemirova was abducted in the Chechen capital Grozny and shot dead.
Russia's leader said it was "obvious" to him that her murder was linked to her professional work.
The UN has urged a transparent investigation into the killing on Wednesday, while the White House says it is "disturbed and saddened" by the crime.
Memorial, the Russian human rights group which employed Ms Estemirova, has accused Chechnya's Kremlin-backed President, Ramzan Kadyrov, or his close associates of responsibility for the murder.
Mr Kadyrov denied any involvement and promised to investigate the killing personally.
'She spoke the truth'
"It is obvious to me that this murder is linked to her professional work and this work is necessary for any normal state," Mr Medvedev said after talks outside Munich with German Chancellor Angela Merkel.
A small rally was held in Moscow in honour of the dead woman
"She did something very useful. She spoke the truth, she gave a very open and sometimes very tough evaluation of what's happening in the country.
"And that is the value of human rights campaigners, even if they make those in power feel uncomfortable."
Unlike his predecessor Vladmir Putin, President Medvedev has moved fast to publicly and explicitly condemn the murder of another prominent Russian human rights worker, the BBC's Rupert Wingfield Hayes reports from Moscow.
He is perhaps aware of the wave of international outrage generated by her killing, our correspondent says.
Ms Estemirova was abducted from her home in Chechnya and her bullet-riddled body was found dumped in a forest a few hours later.
For years she had documented appalling human rights abuses carried out by the Moscow-backed regime in Chechnya, our correspondent says.
Mourning in Grozny
Natalia Estemirova was buried in line with Islamic tradition before sunset on Thursday, in a cemetery in her ancestral village, Koshkeldy, in Chechnya's Gudermes district.
Mr Kadyrov took power in Chechnya after his father was assassinated
Earlier, about 100 mourners gathered outside Memorial's Grozny office on Thursday, some of them weeping.
The dead woman's daughter Lana, 15, said she was stunned by her mother's killing.
"I can't imagine [she] won't be around any more and that I won't be making a morning coffee for her any more," she was quoted as saying by the Associated Press news agency.
Taus Dzhankhotova, 50, said she had been unaware of the killing when she showed up at the office carrying a pizza and melon she wanted to give to Ms Estemirova in thanks for legal help she had provided.
"What for? What for?" she said, crying. "They kill only the good people here. If she was bad, they wouldn't have touched her."
Later, about 50 men and women walked in a slow procession along Prospekt Putin, a central Grozny street, to accompany the dead woman's body as it left in a minivan for Koshkeldy.
While Mr Kadyrov denies he had anything to do with her killing, many of her colleagues in Russia's human rights community are unconvinced, our correspondent says.
Oleg Orlov, Memorial's chairman, blamed the Chechen president personally in a statement on the group's website.
Mr Kadyrov had, he said, "already threatened Natalia, insulted her, considered her a personal enemy".
The Chechen leader condemned Ms Estemirova's killers on Thursday saying they "must be punished as the cruellest of criminals".