Why do people who dream of a beautiful afterlife filled with fountains of milk and honey seem bent on turning this mortal lifetime into a blood-soaked hell? How can people who talk about their love for their prophet wield the machete of hatred and chop down a human being in front of a crowd? These two questions grabbed me by the collar – ate me at my desk – when I first saw the photograph. I wept and bled and remembered those days when we too dreamed of a heaven. This, then, is a story of heaven and hell – theirs and ours.

One February afternoon in Malmö, the image appeared in my Facebook feed [please note, this image may disturb]. And I recognised that street corner, in front of the TSC (Teacher-Student Centre, Dhaka University). That very corner where I once kissed a woman on a Valentine’s day evening. We held hands, took a left turn and walked towards the Ekushey Book Fair. Now, after all these years, there was another woman in the foreground of this photograph, wearing an orange kurta, standing with one hand raised. At her feet, her lover was lying face down in a pool of his own blood – lifeless. As Orwell once described an execution, ‘one mind less, one world less.’ The photograph was taken minutes after Avijit Roy was hacked to death on 26 February 2015. That evening, a neighbourhood of our heaven was invaded by the warriors of Ansar al-Islam. That evening, one of the prophets of freethought was martyred.

That evening, I remembered another prophet of freethought.

I liked – even loved – Humayun Azad as a writer and disliked him as a person. And the dislike was mutual. Azad saw his interviewers as potential assassins, waiting to stab him with their tape recorders. Indeed, Conversations With [My] Assassins was the title of a book in which he collected some of the most controversial interviews he ever gave. Interviewing him was like a bloodsport. One would throw a question at him and watch the glint in his eyes, as if he was calmly calculating the flight path of an incoming arrow. Then he would respond with a sharper arrow, designed to inflict the deepest of provocations or the sternest of put-downs. This would go on for a while, until both parties decided to call it a day and washed off the internal bleeding with a bottle of carbonated drink or a cup of tea.

My last interview with Azad took place during the Ekushey Book Fair in 2004. That evening, as usual, he was sitting at his publisher’s stall, signing books and using the most sophisticated of swear words to curse the mullahs who gather in front of the Baitul Mukarram (the national mosque of Bangladesh) every Friday. He was in a good mood, until I started prodding him about some nasty things he had said about Taslima Nasreen, a feminist writer who has been in exile since 1994. Then we quarrelled for a bit about Bengali feminism. Me, a young reporter at a new English-language daily. And he, the public intellectual who taught an entire generation to think.

That was our last meeting. On the evening of 27 February 2004 Azad was attacked near the TSC by machete-wielding assailants of Jamaatul Mujahideen Bangladesh (JMB) – the same group of holy warriors who are now regrouping as IS (Islamic State) in Bangladesh. He survived, but a few months later he was found dead in his apartment in Munich. He had come to Germany to research the life and work of Heinrich Heine, as a sort of escape from the hell he had been through. Now, 12 years after his death, Azad’s son is also in exile in Germany – fleeing from a new group of machete-wielding assailants, a new group of holy warriors.

These new warriors, Ansar al-Islam, invaded another neighbourhood of our heaven on 31 October 2015. The alert appeared in my Twitter feed. Faisal Arefin Dipon of Jagriti Publishing was hacked to death inside his office in Aziz Super Market, that colourful headquarters of Dhakaite intellectuals and intellectual wannabes. ‘I saw him lying upside down and in a massive pool of blood. They slaughtered his neck. He is dead,’ Dipon’s father told AFP.

This piece of bleak news was preceded by another piece of bleak news. They had also broken into the offices of Ahmedur Rashid Tutul and tried to kill him with machetes and guns. Two publishers targeted on the same day, for the crime of publishing and republishing a book by Avijit Roy. A book on homosexuality – a book celebrating people’s right to love.

Was it not our love of life that turned these neighbourhoods into heaven? Life that did not grant us time to bury our snouts deep inside holy books, life that gave us holier rituals: kissing our lovers as if there was no tomorrow; making that annual pilgrimage to the Ekushey Book Fair; downing pegs of keru at Peacock bar; eating tehari with raw onion at Neelkhet; attending all-night baul concerts at the Art College; taking rain-drenched rickshaw rides through TSC; foraging through the endless bookshelves of Aziz Super Market for that one good read. Was it Dipon who handed me that collection of short stories of Maxim Gorky? This February, I try to remember.

And this February, I receive a SMS. After months of nail-biting waiting, he has made the hijrat. After months of coordination between ICORN, PEN, the Norwegians and the Swedes, they have brought out the family. Another prophet of freethought is now in Norway. I call him and say, ‘Welcome to the free world, comrade.’ Welcome to exile, banished from the heaven – you, I and we!

Find out more about Tasneem Khalil’s book Jallad, published by Pluto Press.

Tasneem Khalil will be in conversation with Ahsan Ahmed, director of the Dhaka Literary Festival, and the BBC broadcaster Razia Iqbal at the Free Word Centre on 24 February, for the first in our new PEN Atlas event series. Find out more