The team searching for a missing Russian woman at tourist-destination Koh Tao in Surat Thani found five pieces of human bones at rocks under the sea, Surat Thani Governor Uaychai Innak said.
He said the bones were found at the dangerous spot where there is a strong whirlpool and strong current.
The bones were found about seven or metres under the sea and the bones were described to be rather new.
He said the bones were sent for DNA test at the Scientific Crime Detection office in Songkhla to compare with DNA sample of the missing tourist, Valentina Novozhenova, 23.
Marine Police chief Pol Maj Gen Kritthapol Yisakhon said the team also found a green t-shirt and snorkeling goggles about 400 metres from the beach of Ao Chalok Ban Kao where the resort the woman stayed is located.
They were found about four to five metres under the water.
Novozhenova disappeared three weeks ago from a Koh Tao hotel the day she was supposed to check out after a week-long stay.