Deaths in paradise: A popular Thai island has become a place of deep mystery.

Nestled in the Chumphon Archipelago off the western coast of Thailand, lies Koh Tao. A 21 square-kilometre island with volcanic origins, carpeted with lush rainforest and rimmed with postcard-worthy beaches.

Yet this little patch of paradise has an unsettling record, one that has earned it an unenviable catalogue of alternative names. ‘Septic Isle’, ‘The Island of Death’, even as Asian Correspondent dubbed it, an island with enough mystery and suspicion ‘to warrant its own CSI franchise’.

Seven tourists have ‘suspiciously’ died on Koh Tao in just three years, several in circumstances that have left their grieving families with more questions than answers.

Just last week, Thai police were forced to reopen the investigation into the April death of Belgian backpacker Elise Dallemagne.

According to local media, the 30-year-old was on the final stretch of an 18-month around-the-world trip when she checked into the Triple B Bungalows at Mae Haad, Koh Tao, on April 19, en route back to the capital, Bangkok.

The Bangkok Post on Saturday claimed Dellemagne checked in under a false surname and refused to supply her passport number.

That evening, three of the rooms, including Dallemagne’s, burned down at roughly 7pm. The owners pegged the blaze as an “electrical fire”, but reportedly declined to file a police complaint, meaning there was no subsequent investigation. It’s believed the young tourist then ventured 2.5km, likely on foot, through the rainforest to Tanote Bay.

It was there, in the jungle, that two locals reportedly discovered her body on April 27. According to The Samui Times, her remains were laying on a rock, “partially eaten by animals, wrapped in T-shirts”.

Local media were unaware of the death at the time, which Koh Tao police ruled a suicide. But the investigation was reopened this week after the The Samaui Times' story circulated internationally via social media.

Speaking about the case to Bangkok Post, Koh Tao police chief Pol Lt Col Chokchai Sutthimek Thursday said that an autopsy performed at Surat Thani Hospital and the Institute of Forensic Medicine at Police General Hospital in Bangkok determined Dallemagne had died from suffocation due to lack of oxygen. A rope, he said, had been found tied to a tree and around her neck. He denied her body had been eaten by animals.

However, there are no reports of a suicide note, and Dallemagne's mother claims she has not received the final autopsy report as promised.

“I do not believe what the police have told us. We fear somebody else was involved," Michele van Egten told German-language news portal Der Farang, according to TIME's translation.

“We’re more and more thinking that the police information is not the right explanation.”

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The backpacker's death follows those of Hannah Witheridge, 23, and David Miller, 24, in 2015. The British duo were found brutally bludgeoned just metres from the former's doorstep at Ocean View Bungalows on Koh Tao's popular Sairee beach.

Two Burmese nationals were later convicted and sentenced to death. The men, apprehended soon after the discovery of the pair's bodies, initially confessed to the crime but later retracted their statements amid claims they were extracted by torture.

It wasn't the only such case to raise eyebrows.

Two years earlier, police concluded that 25-year-old tourist Nick Pearson had drowned after falling into the ocean from a height of more than 15 metres. However, the Brit's parents, who were also holidaying in Koh Tao, were outspoken in their belief that the police investigation was a cover-up for murder.

The same argument was held by friends and loved ones of Isle of Wight bricklayer Luke Miller, 24, who was found dead at the bottom his Koh Tao hotel pool on January 8 last year. Despite a ruling this month by a British coroner that there was no evidence of murder, Miller's family claimed their were inconsistencies in the police reports into his death.

"We know what happened and we will continue to fight for justice. Luke was unlawfully killed," the man's mother Sara Cotton told The Sun.

In 2015, social media users joined relatives of French National Dimitri Povse, 29, who was declared by authorities to have taken his own life in his Ta Chin bungalow on New Year's Day. A note had been left according to Lt. Gen. Somsak Noorod, that read: “Iris, I love you. Suicide seems easy but it is actually difficult.”

However, questions were raised given Povse was found with his hands tied behind his back.

There is one mystery with even fewer answers than these. The disappearance of 23-year-old Valentina Novozhyonova.

The Russian tourist who checked into a Koh Tao hotel on February 11 but never checked out.

According to Bangkok Post, local police believe she may have vanished while diving.

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