A Russian rapper and his Thai girlfriend who were cuddling in the sea were hacked to death by speedboat propellers, police believe.

The holidaymaker, named locally as Enrike Rakhman, 20, and his partner Narada Taichaisong, 20, had been enjoying a romantic trip to Tian Beach on the idyllic Koh Larn island in eastern Thailand on Monday evening, September 25.

As the couple, who had only been dating for a few months, dipped into the water and kissed while floating side-by-side to admire the sunset, a roaring speedboat suddenly barreled into the shallows and struck them.

The propeller blades ripped up Narada's flesh and she was found dead in water. Enrike, who has a catalog of songs on Spotify under his name Mi Ca$a, was also struck but his body has not been recovered.

Police believe Enrike, from Moscow, was killed in the collision and divers are searching for his body.

Speedboat operator Thawatchai Chomphuphuang, 19, allegedly left the scene but was later arrested and remanded in custody on suspicion of causing the death.

Police Colonel Thanaphong Phothi, chief of the Pattaya City Police Station, said officers received a report at around 6 pm when horrified locals found Narada floating face-down in the water.

He said: 'The body of the dead woman was seen floating in the sea but her boyfriend was not found. The injuries on the corpse show she was killed by a speedboat propeller hitting her.

'Witnesses said that she was with her boyfriend when they were struck. We have not found his body and have not been able to locate him. He is missing and possibly dead.

'We quickly identified the speedboat owner and the boat's operator. They have both been tracked down for prosecution. The suspect claimed he did not know that he had struck the couple.'

Narada's body was taken back to the mainland in Pattaya, Chonburi province, for a post-mortem examination. Police said her right breast had been lopped off, and she had wounds on her arms and legs where her skin was torn.

The couple's belongings - including phones, sandals, and notebooks - were found on sunloungers at the beach.

Staff at a nearby massage shop told police that they saw the loved-up couple taking a dip at 4 PM. A speedboat with two engines then arrived to pick up tourists.

The onlookers said the boat had paused for a brief moment - reportedly after hitting the couple - then continued to speed away. Narada's corpse was found shortly after.

Witness Tawan Namp, 35, a worker, said he saw the couple paddling together shortly before the incident. He said they were around 50ft from the shore when the speedboat whizzed past them.

'They disappeared from the water after the boat went by,' he said.

Rescue teams searched the area until 9 pm local time but called off the operation due to a low tide, strong currents and lack of light.

Investigations found that the young couple had been staying at a resort on the island. They had checked out on Monday morning and travelled to Tian Beach on a rented motorcycle.

Police Colonel Thanaphong Phothi said that investigations into the death are continuing.

He said: 'The priority is to find the tourist or recover the body. When he have this evidence the full charges against the suspects can be brought.

'Those responsible will be prosecuted under the law.'