In January 2002, Zelimkhan Yezhiyev's son left his village in Chechnya on a trip to the neighboring republic of Ingushetia.
He was never seen again.
So Yezhiyev did what many Chechens do in that situation -- he traveled to the republican capital, Grozny, and knocked on the door of Memorial, Russia's leading human rights group.
That's where he first met Natalya Estemirova, one of the region's boldest rights campaigners, who became Yezhiyev's main ally in the search for his son.
She helped him file inquiries with the police and take his case to court, and she offered much-needed advice and moral support. His son, 22 at the time of his disappearance, is still missing.
Yezhiyev again sought Estemirova's help when armed men began carrying out raids on his village and subjecting his family to abuse.
With Estemirova's brutal slaying last week, it became clear that Yezhiyev, and hundreds like him, had lost the last person they could turn to for help.
"We could call her day or night, and she would come and help us -- she was a golden person, she always helped me and all those who turned to her for help," Yezhiyev says. "I feel as though I've lost a loved one; she was like a sister to me. My family, my wife, and my daughter all cried when I told them she had died."Forced Closure
Estemirova was found dead of multiple gunshot wounds on July 15, hours after being abducted outside her home in Grozny.
Colleagues say her killing is retaliation for her tireless work investigating executions, kidnappings, and other abuses in Chechnya. They lay blame for the killing on Ramzan Kadyrov, Chechnya's iron-fisted, Kremlin-backed leader, whose militia has been accused of numerous abuses against civilians.
But Chechens are mourning more than the loss of Estemirova. Her employer, Memorial, announced on July 19 that it was suspending its work in Grozny due to concern for the safety of other workers there.
Demonstrators turned out in Moscow on July 16 to express outrage over Estemirova's brutal killing.
Estemirova is the second Memorial worker to have been slain in Chechnya. In April 2006, Bulat Chilayev, a driver for the group's medical program, was abducted and killed.
Memorial says it will remain closed until at least the end of August.
Nurdi Nukhadjiyev, Chechnya's human rights ombudsman -- who critics say merely acts at Kadyrov's behest -- played down the closure of Memorial, saying there were other rights groups in Chechnya to carry on the work.
But Memorial was certainly the largest and boldest of all, the first stop for all journalists reporting on rights abuses in Chechnya.'Nowhere To Turn'
For some, Estemirova's murder and the closure of Memorial remove the last layer of protection for ordinary Chechens.
Shakhman Akbulatov, the head of Memorial's Grozny office, says a string of dismayed citizens have been visiting him since the announcement:
"People come and say that if Memorial shuts down, they won't have anywhere or anyone to turn to for real support and help," Akbulatov says.
But Akbulatov says that even if Memorial opens again, it has lost its most valuable asset: Estemirova.
"We lost a lot with her -- her invaluable experience, her contacts, and her skills. This will deal a blow to Memorial's work," Akbulatov says. "She is, to put it mildly, irreplaceable. We will miss her as a colleague and simply as a person." Climate Of Impunity
Estemirova's death has drawn outrage outside Russia, too.
Amnesty International condemned her killing as "a consequence of the impunity that has been allowed to persist by the Russian and Chechen authorities."
Human Rights Watch said it was "open season on anyone trying to highlight the appalling human rights abuses in Chechnya" and called on Russian authorities to bring Estemirova's killer or killers to justice.
Russian President Dmitry Medvedev has vowed to track down and punish Estemirova's killers. But he has dismissed as "primitive" allegations that Kadyrov or other Russian officials had a hand in her murder.
Kadyrov, for his part, has said he plans to file a slander lawsuit against Memorial's Oleg Orlov, who says Kadyrov is to blame.
Yelena Milasheva, a correspondent for the independent newspaper "Novaya gazeta" who knew Estemirova well, says both the Kremlin and Kadyrov had reason to dislike the slain Memorial worker.
"Kadyrov -- and, I think, federal authorities too -- have been seeking to get Memorial out of Chechnya, because Memorial has irked them throughout the wars and irks them now by tainting the image of stability," Milasheva said. "If Memorial shuts down, it will be a catastrophe."
Human Rights Watch says Estemirova had been documenting "extremely sensitive" cases of human rights abuses when she was murdered.
She had recently contributed to a Human Rights Watch report accusing Chechen authorities of burning more than 20 houses in punitive attacks against the families of alleged rebels.
On the day of her murder, Russian human rights activists in Moscow unveiled a lengthy report which Estemirova had helped research. The report documents atrocities committed by all sides during the two Chechen wars and demands that Putin and other top-ranking officials be held to account for war crimes.RFE/RL's Russian Service contributed to this report.