British tourist Andrew Apperley is believed to have sent disturbing messages about people wanting to "kill him" in the days leading up to his death.
The 38-year-old travelled to a Full-Moon party on the island of Ko Phangan and was reported missing when he didn't return after four days.
According to
Mirror Online, the Sussex native sent texts to his friends and family saying he had "a mad night" and there were guys wanting "to kill him".
In the messages, sent via Whatsapp and Facebook, he also said that there was a "scary guy wearing a face mask".
At one point, he said he thought his drink was spiked and it's believed he may have taken magic mushrooms causing him to hallucinate.
Gloucestershire police are liaising with Thai authorities in a bid to establish what caused his death.
Andrew's brother Richard Apperley spoke to the publication.
"I think he's been murdered. Those messages are signs that there was foul play. I want the Thai police to investigate this properly and I don't want it swept under the carpet.
"He knew Thailand well, he'd been around 10 times and the people he was with say he was in good spirits out there, just trying to have a good time.
"He did take drugs but he didn't go overboard and he knew how to take care of himself. You can see from the messages that he knew he'd been spiked and that he was in danger".
The investigation is ongoing.
Image of Ko Phangan via iStock
