BANGKOK (AP) — Human rights group Amnesty International called on Thai authorities Wednesday to launch an independent investigation into allegations that police tortured a pair of suspects who reportedly confessed to killing two British tourists on a southern island last month.

The tourists were found dead on the rocky shores of Koh Tao on Sept. 15, and police last week arrested two migrant workers from neighboring Myanmar who they said had admitted responsibility for the killings. Police deny suspects were tortured, and said they have DNA evidence that backs up the confessions.