Police Spokesman, SP Jaliya Senaratne said that large amounts of money had been received from overseas for the attacks.
The Easter attack was carried out by a local group targeting Churches and hotels in Colombo, Batticaloa and Negombo.
The Islamic State had claimed responsibility for the attack but there was no evidence to confirm any direct involvement.
Senaratne said that investigations have now revealed that a banned foreign terrorist outfit transferred funds to the group in Sri Lanka to carry out the attacks.
He said that local businesses operated both legally and illegally had also funded the operations of the local outfit to carry out the attacks.
The local outfit was led by Zahran Hashim who was one of the suicide bombers involved in the attacks.
Senaratne said that investigations revealed a number of incidents which occurred before the 21 April 2019 attacks were linked to the bombings.
He said that the investigations were at the final stages and more arrests are expected to be made soon. (Colombo Gazette)