Sri Lanka says two Islamist groups were behind the Easter Sunday bombings.
310 people were killed in the attacks.
Funerals for some of those have begun taking place today.
Sri Lanka's defence minister says it appears the bombings were carried out in retaliation to last month's attacks on mosques in New Zealand.
40 people have been arrested so far.
Police are now looking at whether warnings from international intelligence agencies were ignored or missed.
