A HEARTBROKEN family are searching for answers after the naked body of a young Brit tourist was found in the sea off a beach in Thailand.

Regan Kelly, 28, had just arrived in Thailand for a month-long trip before he went missing on January 3 – with CCTV revealing his final moments.

The building surveyor from Selsdon, south London, was last seen in CCTV footage at the bar of the Mad Monkey Hostel – where he was staying.

Footage shows him talking to a man for hours before the conversation got “increasingly heated,” his family said.

Regan’s sister Laurie Blackall told MailOnline: “We are not too sure what they were talking about, but the conversation seemed a bit confrontational.

“There’s no audio but Regan looked visibly upset.”

She added that her brother got up and left suddenly where he heads towards Patong beach, before the man follows him a mere few seconds later.

Security cam footage from a hotel then shows Regan running, with the unknown man following him nearly 20 seconds later, Laurie said.

At 10am the following day, a watersports instructor had found a naked body in the water off Patong.

Cops sent photos to Regan’s worried family, who had reported him missing, and his identity was tragically confirmed.

Laurie and her dad are in Thailand attempting to find out what happened to Regan in his final hours, and what he had spoken about with the unknown man.

He is thought to be the last person to have seen him alive.

The grieving family are desperately trying to get Regan home, launching a JustGiving page to help bring his body back to the UK to allow a second post mortem to be carried out.

Laurie said: “The detective said he has worked tirelessly but I just don’t know if they want to make it out like it was a tragic accident.

“Don’t get me wrong, it could have been an accident, but something is really not sitting right with me.”

Since Regan landed on December 30, he had been messaging his sister and dad on a regular basis, sharing pictures of his day-to-day activities and letting them know he was safe and well.

But Laurie said that when they hadn’t heard from him on January 3, they knew something was wrong and reported him missing.

Regan was wearing shorts, a Mad Monkey t-shirt, black baseball cap and a cross-body bag over his chest when he was seen running towards the beach.

But his sister said that there was nothing on his body and none of his clothes or belongings could be found on the beach – including his phone.

Laurie said: “Our main focus is getting him home ASAP and continuing to work out what happened, because for us there isn’t any closure, this isn’t a closed case.”

According to Laurie, the man who followed her brother looked like another tourist wearing a white t-shirt and shorts and was “muscly”.

The heartbroken sister added: “I would like to appeal to this guy and for him to tell us what was said, I want to ask why Regan seemed so upset.

“Maybe he was just having a passionate conversation, talking about life.

“Judging by what we saw, they could have been having a very deep conversation.

“But it seems like it was getting heated towards the end – no physical altercations more verbal.”

Laurie described her late brother as “the most beautiful person” who would be missed by his friends and colleagues.

She added: “He’s a qualified building surveyor going to be so badly missed by his team, they rely on him on site. He had an old head on young shoulders.”

Thai authorities have said Regan’s official cause of death was drowning, but his family want a second opinion from a British coroner.