NATALYA ESTEMIROVA is gone now. Her executioners forced her into a car in front of her home in Chechnya and sped away with her on Wednesday morning. She managed to shout that she was being kidnapped, her last known words documenting the beginning of the crimes against her, just as she had documented crimes against uncountable others.

Her killers worked quickly, as if on orders. They drove to a remote place, shot her and left her near the road, killing her in exactly the manner her friends had long feared would be her fate. Her purse was nearby. Her killers did not want it. This crime was about something else.

Ms. Estemirova was an essential member of a tiny circle of the premier human rights investigators in the entire Caucasus  a woman of immeasurable courage, precision and calm. She was a researcher for Memorial, the human rights organization, in Grozny, Chechnya’s capital.

I will step out of character as a reporter and declare it: she was both a trusted source and friend of the last several years, a time when the foreigners still trying to understand Chechnya shrank to an inadequate few.