COLOMBO, Sri Lanka — Sri Lanka’s former navy chief says the father of two of the Easter suicide bombers has been arrested on suspicion of aiding his sons.

Jayanath Colombage, who now is a counter-terrorism expert at the Pathfinder Foundation, confirmed the arrest to The Associated Press on Thursday.

Sri Lankan police could not immediately be reached for comment.

Sunday’s coordinated suicide bombings targeted three churches and three hotels, killing at least 359 people and wounding 500 more. Authorities have blamed a local group, National Towheed Jamaat, for the attack. The group was previously only known for vandalizing Buddhist statues and for the extremist online sermons of its leader, alternately named Mohammed Zahran or Zahran Hashmi.

On Tuesday, the Islamic State group asserted it carried out the assault, bolstering its claim by publishing images of Zahran and others pledging loyalty to IS leader Abu Bakr al-Baghdadi.