It was a tweet that set it all off. An innocuous post that plunged Omer Faruk Gergerlioglu into a personal, administrative and political hell -- and a private trauma that has publicly exposed a growing rift within Turkey’s Islamists.

The offending tweet dates back to October 9, 2016, when Gergerlioglu downloaded a photograph of a peace demonstration, added a comment and posted it on Twitter without a second thought.

The image featured a group of women from the Peace Mothers movement, which brings together Kurdish mothers who have lost children in the state’s interminable counterinsurgency against the Kurds.

The photograph was taken from a World Peace Day gathering, when a group of Kurdish mothers demonstrated behind two symbolic coffins, one draped in the Turkish flag and the other in a PKK (Kurdistan Workers’ Party) flag.

Gergerlioglu tweeted the picture along with a message in Turkish that said: “Looking at this picture, you will understand that this war has no meaning. Mothers the same, flags different.”

A 52-year-old practising doctor and former head of Mazlumder, a leading Islamist human rights group in Turkey, Gergerlioglu is a familiar face on Turkish TV, and his columns are highly regarded in civil society circles.

A hush falls in the waterfront restaurant in Istanbul’s Besiktas district as Gergerlioglu strides purposefully into the room. The piped music is obligingly turned low and waiters approach respectfully with orders placed silently on the table. An elderly waiter insists on a last, free round of tea. He’s Kurdish and an admirer of the “human rights doctor”, he explains. In the southeastern city of Diyarbakir, de-facto capital of Turkey’s oppressed Kurds, Gergerlioglu’s name is greeted with slow nods from leftist activists. “He’s not Kurdish and he’s an Islamist, but he’s a man of principles,” said a local activist.

Gergerlioglu first became known in civil society circles when he served as head of Mazlumder between 2009 and 2011. Mazlumder -- which literally means “persecuted people” – was founded in 1991 to fight for the rights of Turkey’s Islamists oppressed by the secular Kemalist establishment. Then came the 1990s war with the PKK, a bloody conflict between the Turkish state and the Kurdish separatist group that killed around 30,000 people, and Mazlumder earned a reputation for its human rights work during the counterinsurgency.

So, a tweet from Gergerlioglu calling for an end to Turkey’s brutal war with the Kurds should not have kicked off a storm under normal circumstances.

But these were not normal circumstances. The local media in Izmit -- a city around 100 kilometres east of Istanbul, where Gergerlioglu lives -- were the first to pick it up. “They were saying how could a civil servant make such a statement? How can he equate the PKK and Turkish flags?” recounts the doctor-activist.

Gergerlioglu’s story of administrative injustice in the absence of strong democratic institutions, and the very personal trauma he has suffered, is emblematic of the crisis Turkey faces today.

Soon he was headline news in the national press and the victim of a vicious smear campaign on social media.

The nightmare had begun. And it would proceed to spin out of control and seep into every sphere of his very active life.

A compact, neat man with a salt-and-pepper moustache, dressed in the open shirt collar-blazer ensemble that is the uniform of modern, pious Muslim men in the region, Gergerlioglu is not one for extravagant gestures or outbursts. Like a seasoned human rights campaigner, the Turkish doctor traces the chronology of his fall from official grace with meticulous rigour.

Gergerlioglu’s story of administrative injustice in the absence of strong democratic institutions, and the very personal trauma he has suffered, is emblematic of the crisis Turkey faces today.

"That tweet calling for peace was posted in the evening on October 9th. An inquiry was opened on October 11th. On October 13th, my superior at the Izmit state hospital summoned me to tell me that I was suspended,” he explains.

Gergerlioglu did not take the news like a man. He confronted it like a seasoned human rights campaigner.

“I was angry and upset. ‘Are you putting me out of duty for working for human rights?’ I asked my supervisor. He said it was not in his power, that it was the Izmit governor’s decision,” Gergerlioglu explains.

Suddenly the former AKP supporter, who had once run for local office on the ruling party’s list, was being caught in the purge gripping Turkey.

Meanwhile the online trolling just got worse. Gergerlioglu’s social media accounts were hacked, his friends were sent nasty messages, his female associates received obscene insults, and his Facebook page bore the message, “God Bless Turkey. We Will Demolish Turkey’s Enemies.”

A stickler for justice and believer in the rule of law, Gergerlioglu made a detailed report of the online harassment and took his file to the prosecutor’s office. But the prosecutor seemed unimpressed and tried to put him off, telling the human rights campaigner that an investigation would take time.

Months later, nothing has emerged from the prosecutor’s office and Gergerlioglu is incensed. "I issued an appeal for peace and I immediately lost my job. But not one of the people who attacked me violently online has faced any censure or punishment in the past seven months," he notes.

The death threats from what he believes are ultranationalists keep pouring in, Gergerlioglu has gone all the way up to the president and prime minister’s petitions offices and yet, nothing has happened.

"I was used to receiving threats on behalf of the human rights organisation I was leading. But this time, it was very personal – they were directed at me and the people around me. I felt lonely and desperate,” he admits.

The very personal impact of the witch-hunt surfaces time and again in testimonies from victims of the government’s purges. Gergerlioglu repeatedly talks about the government’s “hands entering your neighbourhood, entering your private life”.

An extraordinarily active man, who serves or presides on several charitable boards and associations, Gergerlioglu has seen his cherished voluntary work reduced to nothing.

The lung specialist used to be on the executive board of a committee building a local mosque in his Izmit neighbourhood. Shortly after the targeting began, the board realised that some authorisations for the mosque construction, which should have come through quickly, had been withheld.

It was due to his presence on the board.

"I was made to understand that, as long as I was a member of the council, they would never get permission from the authorities to build this neighbourhood mosque. My friends on the board asked me to resign. I know the law very well, this is totally illegal. But when I confronted the president of the board, he said, ‘I know this doesn’t exist in the law, but because of our situation, it’s better if you just resign.’"

Gergerlioglu didn’t think so. “I told him you are humiliating my honour with my family and friends in my neighbourhood. I won’t let this go. I will take this to the end. You will be in the media as well. You can’t be that arbitrary.”

Once again, he filed complaints and pushed his petition up to the prime minister and president’s offices.

But nothing happened. The system killed him.

“In the end, I did resign -- for the sake of the mosque. But it was so unfair.”

Next, it was the parents’ association at his 12-year-old son’s school. “I didn’t want to be on this board, but I did it for my son, Haroun,” he explains.

One day, the board members summoned Gergerlioglu and informed him that since he was suspended from his hospital post, he could not be part of the school board.

“I was very upset. I felt like my neural system had turned upside down,” says Gergerlioglu.

He asked for an explanation and was told that the school had received a letter from the education board. “I said I wanted to see the letter, and when I did, I was shocked. I saw something that could never exist under the rule of law. The letter said those who have been involved in FETO (Fethullah Gulen Terrorist Organisation) cannot enter public institutions. I said this was a scandal. I wanted a copy of the letter, but he [the school principal] didn’t want to give it to me and we started pulling the letter between us.”

Gergerlioglu explains that he’s a doctor and a human rights activist, not a member of the Gulen movement. But that, for him, is besides the point. “These people cannot enter hospitals, courts, public institutions, this is ridiculous. Where is the rule of law?” he fumes coldly.

Of all the travails that have befallen him, the impact it has had on Haroun, the youngest of his three children, is particularly difficult.

"The most terrible thing was the night my little boy came home and asked me, ‘Dad, what crime have you committed?’ for being taken off the school board. Haroun told me he had to lie at school when they were asked about their dads’ jobs. He told the class his dad is a doctor in a hospital even though he knew I was fired,” recounts Gergerlioglu.

Gergerlioglu’s break with the ruling AKP is an indicator of some of the tensions within Turkey’s Islamists that tend to be overlooked in the media, where the old Islamists v. secularists dichotomy still overshadows the coverage of the country.

When the AKP shot into the national political scene in the early 2000s, Gergerlioglu was a party supporter, the ideals of a democratic opening with liberal market economics being a perfect ideological fit for the pious doctor after the excesses and mismanagement of the military era.

In the 2007 presidential election, he voted for the party and two years later, as chairman of Mazlumder, Gergerlioglu saw his mission of championing freedoms as consistent with the AKP’s vision for a modern, liberal Turkey.

In the 2011 general elections, Gergerlioglu even ran for office on the AKP list although he did not win a nomination.

“But from 2012, I started to notice undemocratic AKP practices and policies, including discriminatory measures,” recounts Gergerlioglu.

Then came the 2013 Gezi Park protests in Istanbul’s iconic Taksim square.

As the police cracked down with excessive force on peaceful civil rights protesters, Erdogan dismissed the demonstrators as çapulcu, or looters. Gergerlioglu, along with two dozen Islamist public figures, signed a declaration condemning the “state arrogance” against the protesters.

“Ignoring Gezi Park protestors’ demands, and subsequently labeling them as ‘plunderers,’ reflects the arrogance of a political power that believes it is the country’s landlord,” the statement noted.

Gezi Park marked a turning point for him as well as for leftists and human rights defenders within the Islamist camp.

“Since Gezi, there has been a split in the Islamist camp. During that event, we saw that the government was giving up on democratic rights and liberties,” he explains.

More recently, the tensions within Islamist ranks spilt into the human rights sphere when Mazlumder, the group Gergerlioglu once led, experienced a putsch of sorts.

In a hastily executed move, the Istanbul wing of the group -- which wanted to focus only on atrocities committed by “terrorists” and not the state – kicked out the Ankara branch members, who were recording violations on all sides in the Syrian and Kurdish conflicts.

It’s part of a crackdown on all dissent that has permeated even Islamist human rights groups.

“Erdogan in the beginning was interested in gaining popularity, he was never interested in tackling human rights issues,” says Gergerlioglu. “He’s losing support from religious people and he’s disappointed peace and human rights activists like me.”

The principled Islamist human rights defender however refuses to be silenced. An opponent of the proposed constitutional changes being put to the Turkish electorate on April 16, Gergerlioglu writes for a number of opposition papers and websites, and maintains a regularly updated blog.

He has also addressed “Hayir” – or No – campaign events, explaining why the Turkish people would be better served if they vote “No” in the April 16 referendum.

But one morning in March, the front page of his blog featured a prominent banner calling for an “Evet” – Yes – vote in the upcoming polls.

"Oh that,” exclaims the doctor, breaking into a rare smile. “It's Google’s fault. They were the ones who sold the ad space on my blog and I can’t seem to do anything about it," he concludes with a resigned grin.

Six months ago, when he experienced his first pernicious barb on the Internet, Gergerlioglu thought he could battle that assault and that justice would be served. Today, he knows better. And still, he won’t stop. His packed schedule these days includes panel discussions, conferences, TV appearances, deadlines for columns, and he continues to be a prolific tweeter, spreading the “Hayir” message online.

If Twitter helped spark his fall from official grace, it is also providing him with a platform to reach Turkish language followers.

Since his fateful October 9 tweet calling for peace, the number of Gergerlioglu’s followers has climbed from around 10,000 to more than 23,000 followers.

“It’s the only thing that has progressed in my life in recent months,” he jokes.