One of the Sri Lanka suicide bombers was previously arrested by police and then released, a senior Sri Lankan government spokesman told CNN 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, Sudarshana Gunawardana said.
"It was the suicide bomber of the Cinnamon Grand bomb attack who was released earlier," Gunawardana 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 across the country.
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.
Police spokesman Ruwan Gunasekera said the elder Ibrahim was is in custody, as are all other members of the Ibrahim family police are aware of in the country.
CNN has not been able to reach Mohamed Yusuf Ibrahim or other members of his family for comment.