Divers have been searching the sea close to where the body of Hemsby woman Hannah Witherirdge was found on a Thai island.

%image(14962799, type="article-full", alt="This photo of Hemsby student Hannah Witheridge, 23, has been released by her family who said she was a loving young woman who "poured joy into the lives of all who knew her".")

Five days after the former University of East Anglia student was killed on the holiday island of Koh Tao, Thai police admitted they were finding the investigation 'difficult' but moved to reinvigorate the search for those responsible.

As a dive team yesterday scoured the seabed close to the beach where Miss Witheridge was killed along with fellow holidaymaker David Miller, 24, on Monday, officers said they now believe the attack may have been carried out by three people and two weapons were used.

The development comes after police questioned 13 people, including two British men and a group of Burmese migrant workers - before ruling them all out as suspects when the results of DNA tests were returned.

While Norfolk Police said the investigation remains with the Thai force, Norfolk's police and crime commissioner Stephen Bett has commented on the investigation. He told the EDP he wanted 'no stone left unturned'.

%image(14963129, type="article-full", alt="David Miller, 24, of Jersey, was killed with Hannah Witheridge, on Koh Tao.")

Mr Bett said: 'Since the news broke about the horrific events in Thailand I have been following developments closely and my thoughts remain with the family and friends of Hannah and David.

'Obviously the investigation is currently a matter for the Thai police but I know officers from Norfolk Constabulary continue to support Hannah's family during what must be an impossible time. As far as the investigation goes I would want no stone left unturned to ensure those responsible are brought to justice as swiftly as possible.'

According to local reports, residents of Koh Tao have offered a reward of 100,000 baht for clues leading to an arrest.

Yesterday, a spokesman for Royal Thai Police insisted officers are 'working around the clock to find the culprits' amid fears the investigation has stalled. Police Colonel Kissana said it was 'difficult to say' if the killers were still on Koh Tao, adding: 'It's quite difficult at the minute to identify the suspects. Looking at the time and place this crime happened - it was dark, late night, early morning.

'We are committed to finding the culprits.'