Police have released a CCTV image of the man they want to speak to in connection with the "gruesome" murder of two British tourists in Thailand.
The image shows what appears to be an Asian man who police say was acting suspiciously as he left a beach party in Koh Tao.
In another photograph, the victims - David Miller (24), from Jersey, and Hannah Witheridge (23), from Great Yarmouth - are seen walking hand-in-hand.
It was taken in the hours before their bodies were found semi-naked on a beach.
The manhunt that followed Monday's discovered originally centred on an apparently British backpacker, but Thai police now believe someone from the migrant worker community could be involved.
A bloodstained hoe, believed to be the murder weapon, was found nearby.
"We are focusing on migrant workers because of the surrounding witnesses and evidence, including the video footage," Major General Kiattipong Khawsamang said.
"We are sweeping hotels, bars, businesses and residences of migrant workers on the beach to find the suspect."
Police say they are following a number of leads.
Some 70 officers are now on the island and defence minister Prawit Wongsuwan said police hoped "to make an arrest as soon as possible".
Ms Witheridge's father Tony said his family was "distraught" at receiving "the most devastating news".
Meanwhile, Mr Miller's former headmaster at Victoria College in Jersey, Alun Watkins, described him as a "bright young man and a talented artist" and said his death was "hard to comprehend".
Friends have paid tribute to the victims on social media.
Hannah Witheridge was one of those found dead | Image: Facebook
Mr Miller's girlfriend, Jessy Howorth, said: "My best friend and the love of my life. We were meant to have so much more time together but I'll continue loving you everyday forever."
Friend Ellie Griffiths said: "So shocked and upset to hear about the death of such an incredibly warm, charismatic, smiley and insightful person.
"Your absence on this planet will be missed and often thought about, I'm so pleased and honoured to have known you Dave."
A Facebook tribute page was set up in memory of Miss Witheridge.
Kal Sylvan Holmes, a friend, said: "Just found out a friend from school was murdered in Thailand. I feel sick and upset."
The victims' bodies, found roughly 100 yards from the scene of a beach party, were taken away in blue body bags.
Police Colonel Prachum Ruangthong said: "The man was chopped in the back and on the side of his head, while the woman was chopped in her face. It's very gruesome."
Local people gathered on the beach last night for a candlelit vigil in memory of the pair.
Prime Minister General Prayuth Chan-ocha said: "This should not have happened in Thailand. It will affect our image in the eyes of international countries."
