Up to 100,000 people took part in the funeral of murdered human rights lawyer Tahir Elçi yesterday. The cold and grey Diyarbakir morning was a fittingly sombre atmosphere for the long walk accompanying his body from the morgue to the Yeniköy cemetery. He was a principled and eloquent advocate for peace and human rights, prepared to speak up for what he believed in, whatever the cost to himself and irrespective of the interests he challenged. He will be very sorely missed.

In his life, Tahir Elçi achieved remarkable things. In the 1990s, as a lawyer in Cizre, one of the most troubled corners of south-east Turkey, he defended the rights of those detained, tortured and forcibly disappeared when it was scarcely possible to do so, risking his own life in the process. When he was forced to leave Cizre, he continued his work in Diyarbakir, as a preeminent lawyer taking cases to national courts and the European Court of Human Rights and worked together with national and international human rights organizations. He later became head of the Diyarbakir Bar Association, leading fact-finding missions across the south-east of Turkey. A founding member of Amnesty International in Turkey, he has been a friend and guiding voice to us for longer still.

Tahir defended the rights of those detained, tortured and forcibly disappeared when it was scarcely possible to do so, risking his own life in the process. Andrew Gardner, Amnesty International's Turkey researcher

Not everyone welcomed his views. Most recently in October, critiquing the government’s role in the breakdown of the peace process, he said “the PKK is not a terrorist organization, it is an armed political movement with considerable support”. This led to a campaign of intimidation and harassment against him. He was detained and charged with “making propaganda for a terrorist organization”, facing seven and a half years’ imprisonment, this was a ridiculous assertion against a man who was also a courageous critic of PKK abuses. Amidst the furore came death threats via telephone and social media.

His death on Saturday came suddenly, with a single bullet to the head. It followed a press statement he made at a historical site in Diyarbakir which still bears the marks and scars of clashes between the youth wing of the PKK and state forces. His last recorded words were “we don’t want guns here, clashes, or [police] operations.” The circumstances of his killing are far from clear. Many have been quick to blame the state for his murder, while the government itself pre-empted the investigation, declaring the PKK responsible.

While his life was dedicated to uncovering the truth, the investigation of Tahir Elçi’s murder already smacks of a cover-up. Lawyers who accompanied the prosecutor to conduct a crime scene investigation on Saturday reported that sounds of gunfire erupted as soon as they arrived at the cordoned off area where he was killed. With the crime scene investigation called off, and the bullet that killed Tahir Elçi yet to be recovered, the chances of establishing the facts and the identity of the perpetrator/s appear remote.

As mourners prepared to bury Tahir Elçi, the sounds of gunfire could be heard. As the funeral drew to a close, reports circulated that a woman had been shot and seriously wounded in the district. By then a police officer had already tweeted “You are next” to Tahir’s wife, Türkan Elçi. In these bleak days for human rights in Turkey, Tahir Elçi’s death creates a void that cannot be filled. He is sorely missed.