The father and son last talked at their family home in the city of Sirnak in southeast Turkey while drinking sweet tea.

The younger man, Hursit Kulter, was staunch in his conviction that Turkey’s Kurdish minority could achieve self-rule through political channels. The 33-year-old worked for a Kurdish-focused political party, the Democratic Regions Party, or DBP.

 After a while, a smiling Hursit bid his father, Hamdi Kulter, farewell, saying he had work to do. His family has not seen him since that day in mid-March.

“Mostly he helped resolve disputes between families,” Hamdi Kulter said. “He left home with nothing more than a laptop and a pen. But the police declared a curfew after he left – he never came back.”

No one seems to know what happened to the younger Kulter, but human rights groups worry that the disappearance may mark a new, disturbing phase in Ankara’s campaign to root out what it describes as Kurdish terror.

During the 1990s, with insurgency by the Kurdistan Workers’ Party, or PKK, at its most severe, many hundreds of Kurds were subjected to enforced disappearances, according to monitoring groups.

Each weekend, across Turkey, women gather in public squares clutching pictures of husbands and sons, pleading to know what happened to their loved ones.

In one prominent 1996 case, 43-year-old Abdullah Canan, a small business owner, disappeared while driving between the cities of Yuksekova and Hakkari. Canan’s village had been razed by the Gendarmerie and he sought to prosecute the operation’s commanders.

His bound and gagged body was discovered more than a month later on a remote stretch of road. He had been shot seven times and his face mutilated with a knife.

“My uncle identified the body,” said Abdullah’s son, Tayyup Canan, now a prominent human rights campaigner in Yuksekova. “I didn’t want to see the body. I didn’t want to remember him like that.”

After a decade of legal battles, the European Court of Human Rights in 2007 ruled that the Turkish state had violated Abdullah’s right to life.

“Everyone is worried that the state will introduce this strategy again,” said Serap Isik, a project coordinator at Hafiza Merkezi, which documents disappearances and has launched a campaign to find Hursit Kulter.

A spokesman at the interior ministry could not be reached for comment. However, the Bianet news agency reported Thursday that the ministry had appointed an inspector to investigate Kulter’s disappearance.

A delegation of the United Nations Working Group on Enforced or Involuntary Disappearances said after a five-day visit to Turkey in March that, “Turkey needs to come to terms with past disappearances, and it needs to do so in a comprehensive manner.”

Since the collapse in July of a three-year peace process between Kurdish insurgents and officials in Ankara, Turkey’s southeast has been beset by waves of tit-for-tat violence.

Insurgents attack authorities with car bombs and guerrilla warfare. Ankara, meantime, imposes sweeping curfews on entire cities and has increasingly deployed fighter jets to target the militants.

In Sirnak, radicalized Kurdish youth – bolstered by experienced fighters – donned Guy Fawkes masks, dug trenches rigged with explosives and clashed with security forces.

In mid-March, the government imposed a curfew on the city and started pummeling Sirnak’s hillside buildings relentlessly with tanks for three months. Journalists and human rights investigators were forbidden access beyond military lines.

At least 37 civilians were killed in the fighting, according to data compiled by Hafiza Merkezi. Photographs shared by activists in the city depict Syria-style devastation: rows of skeletal buildings wasted and buckling, streets strewn with rubble.

On May 27, with the curfew still in effect, Hursit Kulter sent his family a series of alarming messages via Whatsapp, beginning with a common Kurdish phrase used to say farewell and seek forgiveness.

Relatives believe that the security forces had surrounded the building Hursit Kulterhad holed up in.

“I can’t get out anymore,” Hursit said. “Pass my greetings to everyone.”

It was 7:43 in the morning. He has not been heard from since.

Hafiza Merkezi researchers say that Kulter’s vanishing is the first such disappearance in some 15 years, since the enforced disappearances of Serdar Tanis and Ebubekir Deniz, two local Kurdish politicians, in Silopi in 2001.

“These enforced disappearances contain multiple human rights violations,” Isik said. “It causes life-long suffering for relatives and spreads fear in the community.”

Kulter’s family, meanwhile, does not know what to think.

“Nothing is clear,” said one of Hursit’s eight siblings, Cihat Kulter. “We don’t know anything.”

According to Emma Sinclair-Webb, senior Turkey researcher at Human Rights Watch, “not knowing is a form of cruel and degrading treatment.”

The government, meanwhile, is about to pass a bill granting soldiers immunity from prosecution, she added. “The military wants to shore up its impunity. Many crimes happening right now will not be investigated.”

Hamdi Kulter said he fled Sirnak as the March 14 curfew came into effect, moving the family to an apartment a few miles away in the village of Toptepe. He has not lost hope of some day speaking and drinking tea with his son.

“I don’t want to talk about my son like he is in the past,” said Hamdi. “I want to believe that he is still alive.”