Colombo, Apr 25 (IANS): One of the Sri Lankan suicide bombers was previously arrested by police and then released, a senior government official said on Thursday.

Ilham Ahmed Ibrahim, one of two sons of a spice tycoon who blew themselves up in Sunday's attacks, detonated a device at the Cinnamon Grand hotel in Colombo on Easter Sunday, the official told CNN.

"It was the suicide bomber of the Cinnamon Grand bomb attack who was released earlier," the official said.

Ilham Ahmed Ibrahim and his brother Imsath Ahmed Ibrahim were previously identified as two of the suicide bombers in Sunday's attacks which left at least 359 people dead.

Police have confirmed to CNN that they are holding the brothers' father, Mohamed Yusuf Ibrahim, a wealthy spice trader, on suspicion of aiding and abetting his sons.

Sri Lankan authorities have blamed a local Muslim group for the bloodbath although the Islamic State has claimed responsibility for the suicide bombings.