A government investigator says the coordinated Easter Sunday bombings that ripped through three Sri Lankan churches and three luxury hotels were carried out by seven suicide bombers.
An analysis of the attackers' body parts made clear that they were suicide bombers - and while most targets were hit by one bomber, two bombers attacked Colombo's Shangri-La Hotel.
The bombings killed at least 290 people with more than 500 wounded.
Government officials say Sri Lankan police investigating the nine bombings are examining reports that intelligence agencies had warnings of possible attacks and have suggested those warnings may have been ignored.