Malaysian authorities have arrested three suspects linked to a bomb attack in Bangkok last month that killed 20 people and wounded more than 120, the Guardian reports.

Police chief Khalid Abu Bakar told reporters that two Malaysians, a man and a woman had been detained, along with a Pakistani man.

“We believe the suspects can help in the investigation... our arrest was made to assist the Thai police in the Thai bombing investigation,” he said. “Malaysian and Thai police are working closely in cooperation.”

The investigation into the blast in August at a popular shrine, where most of the fatalities were ethnic Chinese, has widened to include countries around Thailand.

Police have suggested the bombing relates to a criminal gang, but there is growing speculation in Thailand that the attack is linked to Uighurs, a Muslim minority in western China.

Thailand forcibly returned 109 Uighurs to China in July. The deportations angered the Uighur community and caused an outcry from human rights groups and the UN, amid fears they could face persecution and abuse.

Many Uighurs have fled to Thailand in the hope of travelling on to Turkey, which has strong cultural links to the group and has sheltered them for decades.

Thai authorities have suggested at least two of the suspects for the bombing are Turkish, and a leaked photo, purportedly of key suspect Yusufu Mierili’s passport, suggesting he was from the Chinese autonomous region of Xinjiang, home to the Uighurs.