Bangkok, Sep 29 (IANS): Thai investigators are looking for three people they believe are involved in the murder of two British tourists on Koh Tao island, media reported Monday.

David Miller, 24, and Hannah Witheridge, 23, were beaten to death and their bodies found semi-naked Sep 15 near a beachside bungalow on the island, the Bangkok Post reported.

Witheridge's skirt was hiked up to her waist and her T-shirt pulled up. She was raped and had a huge injury on her face. Miller had an injury to the back of his head.

A bloodstained hoe (a hand tool used for gardening) was found at the scene, police added.

"Two of the suspects raped and killed Witheridge while another one witnessed the murder," a chief investigator said.

Investigators Sunday seized three guitars from a shelter of Myanmar workers for examination. One of them was hidden without anyone admitting ownership but the other two had owners, police sources said.

Police have also approached seven Thai football players living in Koh Phangan, Koh Samui and Muang districts for DNA samples. They joined a traditional football match in Koh Tao Sep 14.

Meanwhile, results from more than 200 DNA tests conducted in Koh Tao should be ready Monday, the head of the police forensic unit said.

Two different semen samples collected from Witheridge's body, on DNA testing confirmed that the semen belonged to Asians.

The couple had arrived on the island Aug 25.

According to witnesses, Miller and Witheridge were seen partying on the beach with a group of about six people the night they were murdered.

Koh Tao, boasting white sand beaches and azure waters, draws hordes of foreign tourists to its "full moon" parties.