Police in Thailand have said they are investigating new evidence suggesting that the murders of two British tourists may have been due to "sexual jealousy".
Hannah Witheridge (23) was found with severe head wounds next to David Miller (24) on a beach on the island of Koh Tao on Monday.
A spokesman for the Royal Thai Police said that the force was also looking into claims that the pair had a row with a Thai man in a bar before they were killed.
Police Colonel Kissana Phathanacharoen said: "We have discovered fresh evidence which could lead to a new suspect who may have had a relationship or one night stand with Hannah or one of her friends or David the night before they were killed.
"We have asked the Metropolitan Police to go back and make inquiries of Hannah's friends on this matter.
"No lines of inquiry can be ruled out and we believe these crimes could have been motivated by sexual jealousy.
"Police have been made aware of reports that Hannah and David had a fight in a bar with a Thai man before they were killed, but cannot confirm if they are true."
Post-mortem examinations revealed that Ms Witheridge, from Great Yarmouth, Norfolk, died from head wounds while Mr Miller, from Jersey, was killed by severe blows to the head and drowning.
A bloodstained garden hoe, believed to be the murder weapon, was found nearby.
Ms Witheridge's family said that they had travelled to Bangkok on Tuesday to bring their "beloved Hannah" home and find out more about the investigation. Yesterday, they confirmed that her body has returned to the UK.
Thai police are offering a cash reward worth about £4,000 for information that leads to the arrest of the suspects.
Police said on Saturday that they are looking for more than one suspect following unconfirmed reports that the DNA of two Asian men had been found on Ms Witheridge's body.