The bravest woman I have ever met
You would have missed - not noticed - Natalia Estemirova on a bus.
She was very quiet, dark-haired, willowy, with an academic air. You could imagine her being an Anglo-Saxon scholar, perhaps, spending her days bent over old parchments about Beowulf and the like. And about that, you would be dead wrong. She was probably the bravest woman I have ever met.
Brave, because she was following in the footsteps of Anna Politkovskaya, shot dead in the lift in her Moscow apartment in 2006 on the birthday of the then-President, now Prime Minister, of Russia, Vladimir Putin.
Brave, because Natalia - half-Russian, half-Chechen - used to be Anna's translator in Chechnya and after Anna had been killed she knew exactly the risks she was running.
Brave, because Natalia lived in Chechnya, and the local boss there is Ramzan Kadyrov, who critics say is a psychotic warlord. They say he feeds the tigers at his very own private zoo with members of the opposition, that he tortures and rapes and kills at will, with impunity.
Mr Kadyrov, who I'd love to meet one day, denies all that but has been reported to have said: "I've already killed who I should have killed. And I will kill all of those standing behind them, as long as I myself am not killed or jailed. I will be killing as long as I live," which is very nicely put. If only he were my MP.
Mr Kadyrov has specifically denied allegations from the Russian human rights organisation Memorial and others that he was personally responsible for Natalia's murder, saying, "I don't kill women".
Natalia had been working for Memorial, on cataloguing allegations of killing, torture and abuse in Chechnya, many blamed on the Kaydrovites, an armed gang led by you-know-who.
Memorial said that at 8.30 in the morning she was forcefully taken from her home in Chechnya into a car. She was heard to shout out to passers-by that she was being kidnapped. Her body was found in woodland near Nazran, the main city in neighbouring Ingushetia, about nine hours later. She had bullet wounds to the head and chest.
Why move the body from one autonomous region to the next one along? When I last went to Chechnya in 2000, not entirely with the local authorities' permission, there were seven checkpoints between Ingushetia and Chechnya.
With killings and terror still high, I would be astonished if there were not several armed military police checkpoints on that road today.
It was as if whoever killed Natalia was making the simple point that the killers had nothing to do with Chechnya because the body was dumped in Ingushetia, forgetting the slightly more complicated point that whoever did the killing has the power to cross that border at will with a either a corpse or a kidnap victim in the boot.
I met Natalia once in 2007, when I was chairing the very first Anna Politkovskaya Award for the Reach All Women in War campaign at the Frontline Club in London. She was graceful, honoured by the award and somehow - and I struggle to find the right words - shy, abashed at all the fuss that put her at the centre of all this attention.
She was also absolutely firm that she must be exact, accurate in how she did her job. I sensed that what saved her from being overcome, paralysed by fear was her concentration on detail: what time did the men come, what did they look like, precisely, what did he/she hear, see, smell.
The more accurate her cataloguing of hopelessness, the more difficult it would be to deny the detail of the allegations. It was probably that accuracy, that insistence on getting it right that made her such an enemy of whomsoever wanted her out of the way.
Documenting human rights abuses sounds like a very boring and worthy thing to do. But what it actually means is sitting down with someone whose heart is bursting with fear to talk about a loved one.
And the witness can be desperately conflicted. By telling the story the witness may end up dead him or herself. By telling the story he or she may worsen the lot of the loved one - who may be tortured more, or even killed.
So the witness has to put an awful lot of trust into the documenter - and that was Natalia's great strength, and that great strength is the thing that got her killed.
"There is no shred of doubt that she was targeted due to her professional activity," said Tanya Lokshina, of Human Rights Watch in Moscow. Amnesty International's boss, Irene Khan, described Natalia as 'a courageous and inspiring woman,' adding: 'Human rights violations in Russia, and especially in the North Caucasus, can no longer be ignored. And those who stand up for human rights need protection.'
Mariana Katzarova, of Reach All Women In War, put it more simply in an email to me: "They killed Natalia Estemirova today...it is sickening. We lost our Natalia.'
May she rest in peace.