THE ex-boyfriend of murdered Essex University student Hannah Witheridge believes police have "pinned" the murder on two men, according to a friend.

Hannah, 23, and fellow backpacker David Miller were killed last month while on holiday on the Thai island of Koh Tao.

Two Burmese men - bar workers Zaw Lin and Win Zaw Htun, both 21 - have reportedly appeared in court accused of the killings.

But concerns have been raised that the two men are innocent "scapegoats", and a petition signed by more than 100,000 people was handed into 10 Downing Street today demanding a new, independent investigation into the deaths.

Alexandra Boyles, 28, a technology project manager living in London, said Hannah had split with her boyfriend just four months before going travelling and he had been left "heartbroken" at her death.

Ms Boyles declined to name Hannah's ex-boyfriend but said he had criticised the police probe into her death on Facebook.

Speaking at a demonstration in Whitehall as the petition was handed in, she said: "I never met her but I know her ex-boyfriend - it is just too close to home. It is really, really shocking. Just horrific.

"I have spoken to her ex-boyfriend and he is absolutely distraught. It was Hannah's birthday a couple of days ago and he was absolutely heartbroken.

"He is posting so many stories on Facebook about police corruption in Thailand and trying to expose it to people.

"He thinks it is a corrupt case and they have pinned the blame on these two men."

She added: "There should be a new, independent investigation - but it may be too late. They have buried the bodies and it is going to be really hard to dig them up.

"And I think they would have planted the DNA by now."

Hannah, from Great Yarmouth, reportedly died from head wounds while David, 24, from Jersey, is said to have died from drowning and a blow to the head.

The families of the two men accused of their killings have told the BBC they do not believe they committed the crimes.

Campaigners claim Thai police often blame crimes on Burmese migrant workers and their investigations cannot be trusted.