Police searching for a Norwich backpacker missing in Thailand since 2008 have welcomed a positive response to an appeal to find two British men photographed near him.
Danny Hall, 35, has not been seen since leaving an beach party on the island of Koh Pha Ngan in February 2008.
Norfolk Police made an appeal on BBC Crimewatch on Thursday night showing a picture of the two men.
Police said they had received 25 calls and eight names had been suggested.
Det Ch Insp Andy Guy, from Norfolk Police, said Mr Hall had last been seen at an "after party" at the island's Back Yard Bar at around midday on 25 February.
He added: "Many of the party-goers at the Full Moon party would have been British and five years later would now be living and working back in the UK."
He said a key line of inquiry was a picture featuring Mr Hall standing on the edge of the photogaph, with two men in the centre, apparently looking at him.
One of the men is topless with a goatee and shaved head.
Mr Guy said the men are thought to be British and detectives would like to speak to them as witnesses.
Officers would also be interested in speaking to any of the other people in the photograph.
After the final sighting, Mr Hall spoke to two friends on the phone but was never heard from again.
He had never been reported missing before and had no reason to vanish, said Mr Guy.
Mr Hall's belongings were found at the Lam Son bungalow where he had been staying.
It was later established that no money had been withdrawn from his bank account for the three days prior to his disappearance.