Senior Deputy Inspector General of the Criminal Investigations Department Ravi Seneviratne testified before the country's Parliament Select Committee (PSC), which was appointed in May to investigate the April 21 attacks, that the suicide bombers were inspired by the IS theology but there was no evidence directly linking them to the group.
He said on Wednesday that investigations were ongoing to probe if there were more suspects linked to the bombings which targeted three churches, three luxury hotels and two other locations, Colombo Page reported.
Seneviratne told the panel that remnants of the National Thowheeth Jamaath (NTJ), the group that was held responsible by the government for the attacks, had persuaded the IS to claim the bombings.
Director of the Criminal Investigations Department Shani Abeysekera told the committee that all those involved in the terror blasts had either died or arrested and the country was returning to normalcy.
Abeysekera said since the attacks, large stocks of weapons and ammunition had been seized and further investigations were ongoing.
The police said there were over 100 suspects in custody to date, who were directly or indirectly linked to the suicide blasts and security forces were continuing to conduct island wide operations to catch more suspects.
Seneviratne also said that he was not satisfied with the action taken on the prior warnings received before the bombings one of the most brutal attacks in the island nation since the civil war ended in 2009.
Sri Lanka's former police chief Pujith Jayasundara and former Defence Secretary Hemasiri Fernando are currently facing criminal charges over their alleged negligence in failing to prevent the bombings.
( With inputs from IANS )