A local extremist group linked to Al-Qaeda was responsible for the murder of three prominent Maldivians, including a journalist missing for more than five years, an independent commission in the Indian Ocean island republic has found.

The Presidential Commission on Investigation of Murders and Enforced Disappearances said Ahmed Rilwan Abdulla, a reporter with the independent Minivan News website, was abducted on August 8, 2014 and murdered at sea.

Husnu Al-Suood, the president of the commission which was recently established by the Maldives government, told reporters in the capital Male late Sunday that the reporter popularly known as Rilwan received death threats from the group operating under the name Bilad-al-Sham on Facebook.

Al-Suood said the group was also responsible for the assassination of a moderate legislator in 2012 and liberal blogger Yameen Rasheed in 2017, and the attempted murder of another liberal blogger in 2012. 

Rilwan's disappearance sparked international concern, with the UN and rights organisations pressing then strongman president Abdulla Yameen to look into his case and ensure the safety of independent journalists.

The commission said Yameen's government covered up his murder in the otherwise peaceful Indian Ocean archipelago known for its luxury tourism.

It said the group was also responsible for arranging for Maldivians to travel to Syria and join the ranks of Islamic extremist fighters.

Maldives, a nation of 340,000 Sunni Muslims, is known to practise a liberal form of Islam.