A British woman has died after being stabbed at a backpackers' hostel in Australia.Mia Ayliffe-Chung, 21, was killed during a double attack near Townsville, north Queensland. A British man in this thirties was also severely injured and is thought to be in a critical condition in hospital, the BBC reported A dog was also killed and a 46-year-old local man was injured in the attack, which happened in front of up to 30 people on Tuesday night, reported The Guardian Police have arrested a 29-year-old French male suspect, who reportedly said the Arabic phrase "Allahu akbar", meaning "God is greatest", during the attack.They are investigating his possible motivations, including extremism, mental health issues and drugs, reported the BBC . It is being treated as a murder case, rather than a terror attack.Ayliffe-Chung is thought to be from Derbyshire and reportedly visited Bali before making the journey to Australia. She had been documenting her three-month trip on Facebook.She had spent three days working on a farm and working in a bar before she was killed, the BBC reported.Amy Browne, 19, a bartender at the bar where Ayliffe-Chung was a waitress, said: "Mia was honestly the most bubbliest and most caring girl I knew," the Press Association reported.She added that Ayliffe-Chung had a "gorgeous personality" and "always had a smile on her face".Menna Rawlings, the British high commissioner to Australia, is travelling to the area of the attack. A spokeswoman for the commission said: "We are working with local authorities and providing support to the families after one British national was killed and another was critically injured in an incident in Australia," the BBC reported "Our thoughts are with the families at this difficult time."