The family of murdered backpacker Hannah Witheridge said their "lives are shattered once more" after revealing their eldest daughter Laura has also died.
Hannah, 23, and pal David Miller, 24, were bludgeoned to death on a beach in Koh Tao, southern Thailand, in 2014.
Five years and one day after they were killed, Hannah's family revealed her sister Laura, 30, has also died following a battle with an illness in hopsital.
In a heartbreaking tribute, they described the pain as "indescribable".
The family, from Hemsby, Norfolk, said: "We confirm that our beautiful girl Laura passed away on Monday, September 16.
"Laura had been gravely ill and was being treated in hospital.
"Our hearts are broken, our lives are shattered once more.
"The pain of this loss is indescribable and our family very much need time and privacy during this unbearable time."
The girls' mum Susan, 56, wrote on Facebook : "Can’t believe we lost our beautiful girl x a strong woman who loved in an amazing way xx memories remain x always I will remember times gone by us four xx burley x America x I’m so sad for all who knew Laura Daniels and was loved by her xxxx"
In a further emotional post, she called Hannah "an amazing woman."
Hannah was murdered with David, from Jersey, in September 2014.
The student was also raped and her half-naked body was dumped on a beach.
It emerged last month the two Burmese migrants convicted of their deaths would be executed after their appeals were thrown out by the court.
Laura, however, was unconvinced the migrants were the killers.
Since the student's killing, the Witheridge family were targeted by trolls and sent disturbing photographs of the murder scene.
Last year, Laura spoke out about a sadistic internet troll who targeted Hannah's grieving family with grossly offensive posts which compounded their suffering.
She also led appeals to raise money for her family to attend the trial in Thailand.
Writing poignantly on the Go Fund Me page, she said: "The past year has thrown our lives into disarray, tarnished our trust in anything and everything and made us question humanity.
"On my darkest days, I think about the people who have thrown themselves out of planes, run significant distances and those who have sacrificed precious pounds from tight budgets to support us.
"It is in these selfless acts of kindness that I see reason to keep putting one foot in front of the other."
More than £17,000 was raised, largely through donations by kindhearted strangers.
