BBC journalist Hanna Yusuf, whose recent work included an investigation into working conditions at Costa Coffee stores, has died aged 27.
The BBC's Fran Unsworth, director of news, said Hanna was a "talented young journalist who was widely admired" and her death was "terrible news".
Her family said they were "deeply saddened and heartbroken" and hoped her legacy "would serve as an inspiration".
She wrote for the BBC News website, and had also worked as a TV news producer.
Hanna spoke six languages, including Somali and Arabic, and worked with, among others, whistleblowers and victims of serious crime.
In 2018, she spoke to Zaynab Hussein, a mother of nine who moved to Leicester in 2003 after escaping violence and instability in Somalia. She told Hanna about the hate crime that left her with life-changing injuries after she was repeatedly run over by a 21-year-old stranger in the street.
Hanna's article about Costa Coffee working conditions revealed employees' complaints alleging managers' refusal to pay for sickness or annual leave, working outside of contracted hours and the retention of tips.
A Costa Coffee spokeswoman said in August that an independent audit had been launched "given the serious nature of the allegations".
Last year she also wrote about why some homeless people chose the streets over emergency shelter despite sub-zero temperatures.
Hanna also covered the story of Shamima Begum, who fled the UK as a 15-year-old schoolgirl to join the Islamic State group in Syria.
While working for the BBC News Channel earlier this year, she broke the story that Ms Begum's family had told Sajid Javid, the home secretary at the time, that they were going to challenge his decision to revoke her UK citizenship.
And later, she successfully secured an interview with Ms Begum's lawyer, who accused UK authorities of failing to protect her from being groomed by IS.
Wearing the hijab
Hanna started at the BBC as a researcher on the News at Six and Ten in May 2017, before moving to the BBC News Channel and News at One and the website.
Absolutely heartbroken by this news. Hanna always shone - she was gentle and kind, clever and hardworking. It was a joy watching her career take off after she started out with us at The Pool years ago. My heart goes out to her family and friends. https://t.co/bhk3pfm5j3— Lauren Laverne (@laurenlaverne) October 1, 2019
In 2015, she created a video for the Guardian about her decision to wear the hijab at the time, saying "it has nothing to do with oppression. It's a feminist statement", which was picked up by other websites including Teen Vogue and Everyday Feminism.
completely devastated, hanna was so talented and her work will go on to change lives forever. rest in peace schatje ❤️ pic.twitter.com/2kOQOq8IbB— ikran 🌱 (@ikran) September 30, 2019
Born in Somalia in 1992, she received a Scott Trust bursary to do an MA in newspaper journalism at City, University of London in 2017, following her degree at Queen Mary, University of London.
In a statement, Hanna's family said the death of their "beloved daughter, sister and niece" had come as a shock and asked for privacy.
"Many will know Hanna for her incredible contributions to journalism and for her work at the BBC.
"While we mourn her loss, we hope that Hanna's legacy will serve as an inspiration and beacon to her fellow colleagues and to her community and her meaningful memory and the people she has touched for many years lives on," they said.
They added that they would notify the community about funeral arrangements in due course.
There are no words right now to describe the pain of losing a best friend. Your beautiful smile, laugh and spirit. Your big heart. A rising star who will never be forgotten. You will always be loved and with us. #workwifeforlife 💛💛💛💛 https://t.co/LBs6DiiTjR pic.twitter.com/qn7RiAdYMN— Rianna Croxford (@The_Crox) September 30, 2019
Director of BBC News Fran Unsworth said: "This is terrible news that has left us all deeply saddened... and our utmost sympathies go to her family and many friends. Hanna will be much missed."
John Simpson, BBC world affairs editor, said Hanna was a "brilliant young journalist" who would have been a "major force" in UK media.
Deeply sad that the brilliant young journalist Hanna Yusuf has died. She would certainly have been a major force in the British media if she’d lived. Great sympathy to her family & close colleagues.— John Simpson (@JohnSimpsonNews) October 1, 2019
BBC News at Six presenter George Alagiah also paid his respects in a tweet, saying: "Our newsroom has lost a young journalist of such talent and promise. Our thoughts are with her family and friends."
Katharine Viner, editor-in-chief at the Guardian, tweeted it was "absolutely terrible news that the talented journalist, and lovely person, Hanna has died".
Hanna's fellow BBC journalist Sophia Smith Galer said her friend was "invariably the kindest, smartest and most captivating person in the room".
"We have lost a fierce friend and a force for truth and light which stretched far beyond her journalism to the many lives she touched here at the BBC and beyond," she said.
"We will make sure her legacy of compassionate storytelling rings loud and clear in the time to come and we are going to miss her so, so much."
And BBC chief international correspondent Lyse Doucet tweeted: "You left too soon a world where you shone such a bright light."