Relatives of Hannah Witheridge, whose body was found on a beach alongside fellow British victim, Leeds University student David Miller, hugged each other as they prepared to meet Royal Thai Police at their headquarters in Bangkok.
Miss Witheridge, 23, and 24-year-old Mr Miller were found with severe head wounds on the island of Koh Tao on Monday.
In the face of mounting criticism Gen Prayuth Chan-ocha said: “I apologise that I have spoken too harshly ... I didn’t mean to criticise or look down on anyone. Today I can guarantee that Thailand is still safe ... I wanted to warn (the tourists) to be careful.”
Earlier this week had had claimed that foreigners visiting the Southeast Asian country think “they can do whatever they want, wear bikinis wherever they like ... (but) will they be safe?”
And he was quoted as saying: “Can they be safe in bikinis ... unless they are not beautiful?”
His comments came as the investigation into the murders appears to have stalled with police having no suspects.
DNA discovered on the body of Miss Witheridge has been found not to match British brothers Christopher and James Ware, who had been speaking with officers.
And migrants, who had been questioned after bloodstains were found on some of their clothes, are no longer suspects after detectives revealed no matches were found between them and two sets of DNA found on Miss Witheridge’s body and on a cigarette butt discovered near the scene of the murders.
Royal Thai Police had insisted they had found “strong evidence” in connection with the deaths.
Police said post-mortem examinations had shown Miss Witheridge died from head wounds while Mr Miller died from severe blows to the head and drowning.
Mr Miller, from Jersey, also suffered wounds on his hand, indicating a struggle had taken place.
A bloodstained garden hoe, believed to be the murder weapon, was found nearby.
More than 70 Thai police have been questioning migrant workers and tourists on the island, visiting hotels, bars, homes and businesses as they search for the killer.