A 21-year-old British woman has died after being stabbed at Shelley's Backpackers accommodation in Home Hill in Queensland, Australia, by a man shouting "Allahu Akbar".
The woman has been named locally as Mia Ayliffe-Chung, from Derbyshire.
Police said a 29-year-old French national carried out the knife attack in Queensland. A 30-year-old British man was also left in a critical condition.
Amy Browne, 19, from the Gold Coast, worked as a bartender at the Bedroom Lounge Bar where Mia was a waitress. She told the Press Association: "Mia was honestly the most bubbliest and most caring girl I knew.
"She got along with everyone she met, she just had that gorgeous personality that everyone seemed to enjoy.
"She always had a smile on her face, so innocent and full of life and love. Our memories will be cherished forever and I know she'd want us all to stay positive in the darkest of times. Rest in peace my beautiful friend, heaven has truly gained another angel."
The stabbing happened at an accommodation complex in the Home Hill area of Queensland at around 11.15pm local time on Tuesday, police said.
Queensland deputy police commissioner Steve Gollschewski said all motivations were being considered, including criminal and political - as well as the impact of drugs and mental health problems.
But the fact that the suspect shouted the phrase "Allahu Akbar" - which means God is Greatest in Arabic - had been confirmed as officers were equipped with body-worn video cameras.
Friends paid tribute on Facebook, with Tom Paenga writing: "R.I.P Mia. I know that I will not find someone like you again, so happy, so motivating, in good times and in bad times always you were drawing a smile...
"My condolences to your family and to those who had the pleasure of meeting you. Taken too soon but never forgotten!!!"
And Kyle Godwin wrote: "We really do live in a cruel world. The only good thing to come from this is that heaven really truly has gained an amazing and beautiful soul. I love you more then anything in this world beautiful".
According to social media, Mia was only days into a three-month trip working with animals on a farm and had been posting diary entries on Facebook with pictures - sharing her experiences with friends.
Her latest post, on Saturday, read: "Day 4 done. Just 85 left! Skills achieved; the ability to tell the difference between a rock and a clump of mud and throwing stones really far. The sun is too hot. Stupid Australia."
On July 19, the 21-year-old wrote on Facebook about being away from her family and home: "The hardest thing living my dream, missing the important home things. Graduations, people in hospital, funerals and birthdays."