Police in Thailand are investigating the killing of two British tourists -- David Miller, age 24, and Hannah Witheridge, 23, in southern Koh Tao Island.

Both bodies were found naked with head wounds.

On Saturday, police confirmed that the suspects are Asian, and are now waiting for more DNA results.

(SOUNDBITE) (Thai) ACTING POLICE CHIEF, SOMYOT PUMPANMUANG SAYING:

"The institute in Singapore is testing the DNA to tell us about skin color, eyes color, which will be another step further in identifying the suspects."

Police found the DNA of two people in semen taken from Witheridge's body.

The autopsy also revealed that water was found in Miller's lungs, suggesting he could have been drowned.

On Friday, police collected more DNA from 30 locals and migrant workers in the area.

Tourists were shocked by the news.

(SOUNDBITE) (English) TOURISTS FROM NEW ZEALAND, KATIE JONES SAYING;

"It's horrible and it's devastating. But it's not n