(CNN) Lyra McKee, the young investigative journalist shot dead during violence in Northern Ireland on Thursday, had been widely viewed as a rising star within the industry.

McKee's reporting and writing, inextricably linked to the volatile period of history in which she grew up, had led to international recognition and a high-profile book deal.

"McKee's passion is to dig into topics that others don't care about," Forbes magazine wrote in 2016, naming the journalist as one of the "30 Under 30" talents to watch in the media.

Laura Hassan, editorial director at Faber & Faber, said McKee had a "knack of engaging the head and the heart" when announcing the publisher's two-book deal with the writer in April 2018. "I think Lyra McKee has a long and prestigious writing career ahead of her," Hassan added at the time.

McKee, who was 29, dedicated herself to journalism aged 14, starting a newspaper while still at school in Belfast. Her work as an investigative reporter explored the aftermath of The Troubles, the decades-long conflict between Irish nationalists and British unionists in Northern Ireland that left more than 3,500 people dead.

The reverberations of the sectarian struggle was the setting for McKee's murder in Londonderry, also known as Derry.

McKee had an affection for the region she frequently covered, referring to it in a TEDx talk as "Legend-derry."

"Avoid that Londonderry/Derry thing. I hate that," she added.

McKee was eight years old when the Good Friday Agreement of 1998 was signed. The pact was a turning point, intended to end years of bloodletting in the region.

"We were the Good Friday Agreement generation, spared from the horrors of war," McKee wrote in a piece published in The Atlantic in 2016. "But still, the aftereffects of those horrors seemed to follow us."

On Good Friday, McKee's friends and former colleagues woke to news that she had been killed. "Her death is a major loss to journalism," the National Union of Journalists said in a statement.

'You'll have found your calling'

McKee received global acclaim for her writing in 2014, when a letter she addressed to her younger self went viral.

Discussing her experience growing up gay and closeted at school, McKee wrote: "Life is so hard right now. Every day, you wake up wondering who else will find out your secret and hate you."

"It's going to be okay," she added.

In the same letter, later made into a short film, McKee described her passion for writing that blossomed at an early age and gained her a role on a training scheme for journalists at the age of 15.

"For the first time in your life, you will feel like you're good at something useful," she wrote. "You'll have found your calling."

"You'll meet amazing people. And when the bad times come again -- FYI, your first girlfriend is not 'the one' and you will screw up that History exam -- it will be journalism that helps you soldier on."

In a letter to her 14-year-old self, McKee described journalism as her "calling."

Having left university before completing her degree, she created and ran the online-based "Muckraker Report" website which gave her a platform to research and write months-long investigative pieces.

Her first story for the publication, published when she was 23, explored Northern Ireland's only rape crisis center and its battle to regain funding that had been cut years before. McKee spent five years working on the investigation, she told Ireland-based analytics group Insight News Lab in 2013.

"There are wrongs you cannot fix," she said about the story. "As a younger reporter, I found this so hard to stomach. For me, journalism was about saving the world; if I told the terrible stories, someone would have to do something about them. Someone would sit up and notice."

'She tirelessly pursued the truth'

The following year, McKee's open letter letter was published -- and greater opportunities swiftly followed.

McKee went on to write for publications including the Belfast Telegraph , BuzzFeed, Mosaic Science and Private Eye, frequently exploring the legacy of The Troubles amongst her own generation.

She became an editor for Mediagazer, a US-based site that collates media news reports. "Police have named Lyra as the victim. Making this the hardest and saddest headline we've ever written," wrote Gabe Rivera of the site on Friday morning, sharing a report about her death.

An investigation into suicide rates among the "Ceasefire babies" -- her generation in Northern Ireland born or raised immediately after the Good Friday Agreement -- was written for Mosaic Science and re-published by The Atlantic.

McKee crowdfunded her first book, "Angels With Blue Faces," an exploration of the 1981 murder of Belfast politician Reverend Robert Bradford by the Provisional Irish Republican Army.

"I met Lyra many years ago as a young, determined and ambitious budding reporter," said Tina Calder, owner of Excalibur Press, which worked with her on publishing the book. "Her tenacity, determination, ambition and empathy made her an amazing young reporter and investigative writer ... For years she tirelessly pursued the truth."

That book brought her to the attention of large publishers, and in 2018, McKee was signed for two books by Faber & Faber.

The first of those works, "The Lost Boys," was due to be published in 2020, and is set to document the stories of eight boys who went missing in Belfast during The Troubles.

McKee's rising profile as a freelance journalist and writer also earned her a platform to press for greater acceptance of LGBT people within religious communities.

McKee talks at the TEDxStormont Women event in 2017.

At a TEDx talk in 2017 about the Pulse nightclub shooting in Orlando , McKee urged for a change in religious teaching on LGBT issues.

"I hated myself for much of my life because of what religion taught me about people like me," she said.

"We need to do to one thing that I didn't want to do when I left school at 16 -- we need to have conversations ... and fight for the hearts and minds of those who oppose us."

'A bright light has been quenched'

Shortly before her death, McKee tweeted: "Derry tonight. Absolute madness," alongside an image of police vehicles and rising smoke in the distance.

McKee was described as "a journalist of courage, style and integrity" by Séamus Dooley, the assistant general secretary of the National Union of Journalists, to which the writer belonged.

"She was a woman of great commitment and passion. I have no doubt that it was that commitment which led to her presence on the streets of the Creggan last night, observing a riot situation in the city," Dooley added. "She had tweeted just minutes before being hit by a bullet."

A journalist has been killed covering riots in Derry. Her name was Lyra McKee. She was 29. She recently signed a two-book deal with Faber, who called her a "rising star of investigative journalism". This is her last tweet, sent from the scene of the unrest. pic.twitter.com/0gk1Fa7Du0 — Naomi O'Leary (@NaomiOhReally) April 19, 2019

"A young, vibrant life has been destroyed in a senseless act of violence," added the NUJ's general secretary, Michelle Stanistreet. "Our thoughts are with her partner, family and many friends and colleagues. A bright light has been quenched and that plunges all of us in to darkness."

Lilly Dancyger, who edited a piece by McKee for Narratively, said she "was dedicated to covering the lasting trauma & violence of the Troubles. Devastating to hear she was killed tonight by that same violence."

Next month, McKee had been due to speak at an event to mark World Press Freedom Day, hosted by Amnesty International, about the murder of journalist Marie Colvin, the NUJ said.

Technology journalist and friend of McKee, Matthew Hughes, described her death as "heartbreaking" on Twitter.

"She was one of my closest friends. She was my mentor. She was a groomswoman at my wedding," he wrote. "I can't imagine life without her, and yet now I must. I'm devastated."

Several politicians also expressed their condolences, and a GoFundMe page was set up in memory of McKee, raising more than £15,000 ($19,500) in a matter of hours.

Many who knew her also urged police to identify her killer.

"She was shot and killed by a cowardly masked gunman who was intent on ending life," Calder of Excalibur Press said. "Someone in the community knows who lifted that gun, who wore the mask, someone knows who did this. It's time to bring them to justice."

"The new Northern Ireland, of which Lyra was a shining light, does not want violence and destruction," Calder added. "It's time to stand up to those who continue to bring us to our knees in grief. It's time to show them they are no longer in charge."