The journalist Lyra McKee was killed in a riot, in Northern Ireland. Photograph by Jess Lowe

“Hello lovely,” she’d messaged me. “You in Derry anytime soon?” I loved Lyra’s easy way with affection. Twenty-nine years old, she was half my age. We’d become friends through writing and our shared obsession with Northern Ireland. I got back to her that, yes, I would be up to visit my mum that weekend, Easter weekend. I’m from Derry, and Lyra had recently moved there to be with her partner, Sara. It’s a small city in the northwest of Northern Ireland, on the border with the Republic, and, for Lyra, who was born and reared in the capital city of Belfast, it seemed as exotic as Samarkand. She’d talked about her move as though she was emigrating, though the drive takes only about an hour and a half.

I was thinking that I’d ask her if she wanted to go to the Republican Easter parade with me on Monday. I was writing something about the city, and we were both interested in working out why dissident Republican factions were stirring things up. We were also due a talk about the most recent chapter of her new book, which she’d e-mailed me, along with a note that said she was struggling with writer’s block. I felt that she had got into a bit of a panic and had slightly lost her way. She’d find it again. She always did. Lyra’s writing was confident and stylish. She had a voice that rang true. And she was passionate about this book. I would tell her these things.

She messaged back that while I was up I’d have to try the traybakes from a bakery she’d discovered. These are a lethally sweet type of unbaked cake, a Northern Irish speciality for which we both had a weakness, despite the fact that each of us also declared on a regular basis our intent to lose weight. I said that she was to step away from the traybakes. “Are you sure?” she replied. We both liked riffing on silly stuff, particularly when there was writing to be done. We settled on meeting up on Sunday, the details to be arranged. “Epic,” she wrote.

And “epic” was the last word that Lyra ever wrote to me. Because the following night, she was shot dead in Derry.

Trouble on the streets of Derry had been anticipated. It was Easter, when the 1916 Rising against British rule—which paved the way for the partitioning of Ireland, in 1921—is commemorated and old grievances among Irish Republicans are aired. In what became the Republic of Ireland, the matter is more or less settled. The President stands among state dignitaries and observes a parade by the Irish National Army. In the six counties of Ulster that were retained by the United Kingdom, the situation is more volatile. The Troubles, which lasted twenty-five years, saw the paramilitary Irish Republican Army (I.R.A.) engage in “armed struggle” with British and local security forces to try to reunite the island of Ireland as an independent republic. As part of a protracted peace process, the I.R.A. laid down its arms in 1994. Its political wing, Sinn Féin, signed up to the Good Friday Agreement, in 1998. It went on to become the dominant nationalist party, sharing power with the Democratic Unionist Party (D.U.P.). But several small, angry factions regarded the peace settlement as a sellout and are determined to show that they can reignite the conflict.

Murals in Derry make heroes of the I.R.A.’s “freedom fighters” and hunger strikers of the nineteen-seventies and eighties. But the city is also one of the few places in which dissident Republicans have a foothold, their most recent incarnation being the New I.R.A. Several of the group’s key figures participated in notorious I.R.A. atrocities during the Troubles. Some of their younger followers have been radicalized by the old “Brits out” rhetoric; others are marginalized, addicted to drugs or alcohol, or just bored, running wild with a sense of nothing to lose. A recent survey of young people in Derry found that ninety-five per cent of them saw no future in the city.

In 2017, after a period of political stasis and rancour between Sinn Féin and the D.U.P., the power-sharing institutions in Belfast collapsed. Brexit is compounding the instability. All indications show that the U.K.’s withdrawal from the European Union will be economically disastrous for the border region, and Derry is a border city. The dissidents believe that they have been vindicated in their claim that Sinn Féin was duped and that the I.R.A. should have kept up the “armed struggle.” Sinn Féin dismisses them as criminal gangs and traitors. The flare-ups of violence in the last few years are the result of this Republican in-fighting. It is as ridiculous, extreme, and destructive as only family rows can be.

Saoradh, named for the Irish word for liberation, is the New I.R.A.’s political wing. Its Web site, which was taken down after Lyra’s murder, as were its Twitter and Facebook accounts, made an anachronistic reference to “all our martyred dead,” but the group also has posters around Derry promoting mental health, with the slogan “It’s O.K. not to be O.K.” It claims to be “youth focussed.” In reality, the New I.R.A. orchestrates bonfires, hijackings, and riots, carries out “punishment shootings” of teen-agers for “anti-social behaviour,” and plants bombs, which, thankfully, have so far failed to do serious harm. Several children have ended up in court for their involvement with the group. On Facebook, one of its associates proudly displays photos of a young girl, who looks about eight years old, grinning in front of a Republican flag as she pretends to fire a rifle.

On International Women’s Day this year, Saoradh sent “revolutionary greetings to Mna na hEireann [the women of Ireland].” Six weeks later, on the eve of the twenty-first anniversary of the signing of the Good Friday Agreement, young people began to share photos on social media of a convoy of police crossing the River Foyle, in Derry. They were heading up toward Creggan, a housing estate on the western edge of the city. The neighborhood’s location, high on a windy hill, overlooking the curve of the river, with views of the mountains of Donegal, is beautiful, but it is one of the most socially disadvantaged places in the United Kingdom. Its appalling living conditions and lack of amenities were central to the rise of the civil-rights movement in the nineteen-sixties; today, one in three children in Creggan is born into poverty. When the police arrived, they raided a house, and later said that they had been told there were weapons inside. They did not find any.

Boys wearing hooded tracksuits and scarves over their faces gathered. They threw bricks, firecrackers, and then petrol bombs at the police, who by this stage had retreated into their armor-plated vehicles. There was no sense of the old communal fury behind this riot. When I looked at social-media footage afterward, the riot had a staged quality. A British TV crew was present, filming a documentary. A van was hijacked and set alight, then a car. A local freelance journalist who was there, Leona O’Neill, told me about it. “People were standing out on the street, including women with babies on their hips,” she said. “They were chatting with neighbors, watching and filming. There were people dodging bricks.” There was no sense of danger. But that soon changed. “At about 11 P.M., I heard the ‘pop, pop’ sound I knew was gunfire, and I ran behind a wall,” O’Neill said. Almost immediately, she saw that someone had fallen. She heard a woman ask in a panicked voice, “Where’s Lyra?” Then O’Neill heard a scream.

“The Ceasefire Babies was what they called us,” Lyra wrote in “Suicide of the Ceasefire Babies,” an article published by Mosaic, a health-and-science Web site, in 2016. “Those too young to remember the worst of the terror because we were either in nappies or just out of them when the Provisional IRA ceasefire was called.” The essay describes Lyra’s experience of growing up along one of Belfast’s sectarian peace lines and draws on research by a professor at Queen’s University Belfast, which found elevated rates of suicide in Northern Ireland in the post-conflict period. The highest rates were among those who had grown up during the worst years of the Troubles and, more surprisingly, among young people in their twenties—Lyra’s generation.