Maldives vice-president Ahmed Adeeb has been arrested on suspicion of links to a blast on the presidential boat last month.
Police spokesman Ismail Ali said Adeeb was arrested on Saturday at the airport when he returned from an official visit to China.
The September 28 explosion took place aboard the boat when President Yameen Abdul Gayoom and his wife were returning to the capital Male from the airport after a hajj pilgrimage to Saudi Arabia. The airport of this archipelago state is on a separate island.
Mr Gayooom escaped unhurt but his wife, an aide and a bodyguard were injured in the blast.