Valentina Novozhyonova, 23, vanished from her hostel on Koh Tao in mid-February, sparking a police search.

Valentina Novozhyonova, 23, vanished from her hostel on Koh Tao in mid-February, sparking a police search, The Sun reported.

She had checked into the hostel on February 11 and was due to check out on February 16 — but failed to do so.

Valentina Novozhyonova, 23, vanished from her hostel on Koh Tao in mid-February after visiting the resort island.Source:Facebook

A few days later, staff checked her room to discover her mobile phone, passport and camera had all been left behind.

Koh Tao is located in the Gulf of Thailand near the party islands of Koh Phangan and Koh Samui, and was the scene of the brutal double-killing of Brits Hannah Witheridge and David Miller.

Koh Tao is popular with tourists looking for a snorkelling adventure.Source:Facebook

The Samui Times reported the island has been dubbed ‘Death Island’ amid wild speculation regarding the cause of recent deaths among locals.

Valentina was reported to have been visiting the island to go freediving, an activity the area is famed for among backpackers.

Police chief Apichart Boonsrirote said he assigned teams to check all surveillance cameras around the hostel and on the island to find out where she was last seen, The Phuket News reported.

Brit David Miller was killed while visiting the island in 2014.Source:Supplied

Meanwhile, the family of David Miller have appealed for leniency for his killers facing a death sentence.

The 24-year-old was bludgeoned to death with pal Hannah, 23, on Koh Tao in 2014.

Burmese migrants Wai Phyo and Zaw Lin initially confessed to the killings but then retracted their statements saying they were tortured.

They launched an appeal against the death sentences, but the verdict was upheld in Koh Samui this week.

Hannah Witheridge was raped and killed in the horrific double slaying.Source:Supplied

That was rejected this week and David’s family are satisfied the right men have been convicted.

They said in a statement: “The evidence is overwhelming and we feel justice has been done.

“We remain confident that this is the correct decision. We hope that the Thai authorities will show leniency in relation to the death sentence.”

David, from Jersey, and Hannah, of Norwich, were battered with a hoe as they walked to a hotel. Hannah was also raped.

This story first appeared in The Sun and was republished with permission.