CCTV images of what police in Thailand have described as an Asian-looking man have been released in the hunt for suspects in the murder of two Britons.

Investigators said they were looking for a number of people - but have ruled out other British tourists.

David Miller, 24, and Hannah Witheridge, 23, were found dead on a beach in Koh Tao on Monday, having suffered serious injuries in an attack.

The families of both victims paid tribute, saying they would be missed.

In a statement, Mr Miller's family said: "David was an artist by temperament. He had a creative eye that he carried with him through life and in his degree.

"He was hard-working, bright and conscientious, with everything to look forward to.

"David was very giving to his family and friends and we all adored him. He will be sorely, sorely missed."

Ms Witheridge's family described her as "a beautiful, intelligent, loving young woman who poured joy into the lives of all who knew her".

"She was selfless and caring and made each and every day that little bit more wonderful," the statement added.

"Our family are utterly devastated and shocked by what has happened to our beautiful Hannah. To lose her in the way that we have is beyond comprehension. We are heartbroken and no words can possibly describe how we feel."

Thai police said they had CCTV of Mr Miller and Ms Witheridge walking together, and later footage showing a man - described as being of Asian appearance - who is now the prime suspect.

They said they were now focusing their investigation on the Burmese migrant worker community on the island Koh Tao.

Mr Miller, from Jersey, and Ms Witheridge, from Hemsby in Norfolk, were found close to the beachside bungalows where they had been staying.

A garden hoe believed to have been used in the attack was found nearby.

The bodies have been taken to the capital, Bangkok, for forensic analysis and are expected to be returned to their families after that.

Meanwhile, BBC south-east Asia correspondent Jonathan Head said the police's focus on Burmese migrants would be "quite controversial" as Burmese people were "often scapegoated" for crimes in Thailand.

He said police reinforcements had arrived on the island to help with the investigation, along with a consular official from the British embassy in Thailand.

Police still want to speak to a British man who was with the victims on Sunday evening, but the man is probably not a "major suspect", our correspondent added.

Major General Kiattipong Khawsamang said police were sweeping hotels, bars, businesses and residences of migrant workers on the beach.

(BBC)