THE sister of a Vietnamese woman who was tortured by two convicted murderers has said they are evil and should die behind bars.

Nail bar owner Quyen Ngoc Nguyen suffered unimaginable horror at the hands of Stephen Unwin and William McFall, who teamed up after meeting in prison when they were serving life sentences.

Her sister, Quynh, 32, said that for the safety of the public they should never be released.

Speaking through an interpreter, she said: "I don't want to blame anyone but it seems that the Government is too kind to these people, because what they have done is terrible.

"My sister has passed away and nothing can change that.

"But I believe that if these two people were released at some point in the future, then definitely some innocent people could be harmed.

"I think they should never be released, they are evil."

The sisters ran a nail bar in Gateshead, and lived together in Killingworth, North Tyneside, bringing up their children in the same house.

When she heard the news that her sister had been murdered, Quynh could not bring herself to tell their parents in Vietnam.

She described her sister as trusting but also naive.

She has followed the court proceedings, despite the torment of hearing in detail the ordeal her sister faced.

Quynh, holding a framed photo of Quyen, said: "I took all the courage that I have in order to know exactly what happened to my sister.

"But sometimes when I hear the stories from the two defendants, I was so resentful, I couldn't control myself.

"They make up stories that you just cannot imagine how they do things like that."

Quyen came from Vinh, a city in the north of Vietnam, and moved to the UK in 2010 to study business in London.

As well as working in the nail bar Quyen helped Vietnamese people who may not have had the correct documents to find accommodation.