MOSCOW - A well-known Russian rights activist was found slain execution-style on Wednesday, hours after being kidnapped in Chechnya - the latest in a series of brazen murders targeting critics of the Kremlin's violent policies in the war-torn North Caucasus.
The daylight slaying of Natalya Estemirova follows the killings in recent years of reporters, lawyers and activists, and appeared to indicate that Russia remains a place where political murders are committed with impunity.
Russian President Dmitry Medvedev reacted quickly to the murder - in contrast to other recent killings - expressing his condolences, and ordering the country's top investigative official "to take all necessary measures." His press spokeswoman Natalya Timakova said Estemirova's murder appeared to be related to her work.
The slaying came the same day as the release of a report she helped research that concluded there was enough evidence to demand that Russian officials, including Prime Minister Vladimir Putin, be called to account for crimes committed on their watch.
"She documented the most horrendous violations, mass executions," said Tatyana Lokshina, a Moscow researcher with the U.S.-based Human Rights Watch.
"She has done things no one else dared to do," she said.
Estemirova, a 50-year-old single mother, was reported kidnapped Wednesday morning by the prominent rights organization she worked for, Memorial. Chairman Oleg Orlov said that four men forced her into a car in the Chechen capital, Grozny, where she lived. He said witnesses heard her yell that she was being abducted.
About nine hours later, her body was found on a roadside in Ingushetia, which borders Chechnya to the west. There were two close-range bullet wounds in her head, according to Ingush Interior Ministry spokeswoman Madina Khadziyeva.
Estemirova had collected evidence of rights abuses in Chechnya since the start of the second war there in 1999. She was a key researcher for a recent Human Rights Watch report that accused Chechen authorities of burning more than two dozen houses in the past year to punish relatives of alleged rebels.
Orlov accused Chechnya's Kremlin-backed president, Ramzan Kadyrov, of being behind the murder.
"Ramzan already threatened Natalya, insulted her, considered her his personal enemy," he said. "Ramzan Kadyrov has made it impossible for rights activists to work in Chechnya."
Estemirova also worked with the investigative journalist Anna Politkovskaya, another critic of Kremlin policies in the North Caucasus who was gunned down in her Moscow apartment building in 2006. And she aided Stanislav Markelov, a lawyer involved in Chechen rights abuse cases who was shot and killed on a Moscow street in January, along with an opposition newspaper reporter.
Wednesday's killing came a few hours after Russian rights groups presented a report saying that Putin and other top officials should be considered suspects in crimes against humanity that could be tried before an international tribunal.
The 600-page document appeared to be the first comprehensive attempt to collect and analyze accounts of atrocities by all sides in the two wars between separatists and government forces.
There was no evidence that her killing was connected to release of the report. But Markelov was killed as he left a similar news conference at the same office in Moscow, where he had spoken about his efforts to send a Russian colonel who had strangled a Chechen girl back to jail.
Andrei Mironov, a rights activist and former gulag prisoner, asserted that Estemirova's killing, and others in recent months, were clearly sanctioned by government officials.
"First off, they kill reporters, to cut off the front line of information. Then they kill activists. ... They are by definition enemies and they must be eliminated," he said. "This is the Russian state. This is a Russian political system that generates terror, systematic terror."
Both wars in Chechnya were marked by reports of indiscriminate military attacks on civilians - including air and rocket barrages that levelled much of the Chechen capital - summary executions of suspected rebel sympathizers and abductions of civilians by both sides.
At least 484 people were executed without a trial during the wars and another 465 killed in massacres or at checkpoints, said Wednesday's report by Memorial and other rights groups.
It comes at a time when international criticism of Russia over Chechnya has receded. Fighting there has dwindled from major offensives to small, sporadic skirmishes.
The authors of the report acknowledged that in calling for an international investigation they face an uphill battle.
Rights lawyer Karinna Moskalenko told reporters that critics have asked her: "Why do you want to lay bare these wounds?"
"We don't know when and under what circumstances, political or otherwise, an independent investigation of these crimes may be created," said Stanislav Dmitriyevsky, chairman of the Russian-Chechen Friendship Society.
The report claims to find sufficient grounds to hold Russian officials to account for crimes committed under their leadership.
"Numerous detailed testimonies of these atrocities have allowed us to name some of those who should be the first to be taken to court. ... One of them, Vladimir Putin, is the head of the government de jure and the head of state de facto," the report said.
Putin was prime minister when the second Chechen war was launched in 1999. Russia's brutal strategy during his presidency was seen as one of the main factors behind his extraordinary popularity.
Many of the allegations of abuse in Chechnya have been directed against Kadyrov and his security forces.
Kadyrov has overseen massive efforts to rebuild the region and persuaded hundreds of former militants to join his feared security units. But as he has consolidated his power, many critics and political rivals have been killed - two of them in broad daylight on the streets of Moscow.
His office declined to comment on the Estemirova killing.
Although Chechnya has been comparatively quiet in recent months, violence in neighbouring North Caucasus regions has spiraled. The president of Ingushetia was severely wounded in a suicide bombing last month and the top police official in Dagestan was killed by a sniper.
Associated Press Writer Jim Heintz in Moscow contributed to this report.