The family of a university graduate brutally murdered and found in a burning car said she was "an amazing, special person".
Catherine Wells-Burr, 23, was discovered in her red Ford Focus, which was abandoned in a field by the side of a road near Ilminster, Somerset.
A 32-year-old woman was arrested on Thursday night on suspicion of murder and remains in police custody. Two men also arrested have been eliminated from the inquiry, Avon and Somerset Police said.
The Bath Spa University graduate leaves her mother Jayne, father Phil, sister Leanne, and boyfriend Rafal Nowak.
In a statement they said: "We have lost our beautiful Catherine; she was full of character, she was caring, loving, and had a bubbly personality. She had a wonderful sense of humour, and was an amazing, special person.
"Catherine had achieved so much in her short life and had worked so hard to gain her Bachelor of Honours in Business Management, gaining a 1st class degree from Bath Spa University.
"She was so happy starting her life with Rafal and excited about their future together.
"We have found this hard to understand why someone would have done this to her. There are no words to express how we feel about what has happened to her early on Wednesday morning. We desperately need to know why. She will be sadly missed."
Firefighters were alerted to the blazing five-door vehicle by passing motorists shortly before 6.30am on Wednesday off the A358 in Ashill. Fire crews extinguished the flames and discovered the body of Miss Wells-Burr inside the wreckage.
Avon and Somerset detectives have appealed for witnesses describing her death as "tragic and brutal". The force said the officers were working to establish what happened in the early hours of Wednesday morning that led to the car being set ablaze.