ISIS is also claiming credit.
Via NY Post:
A radical Islamic cleric who uses the burning Twin Towers as a backdrop to fiery online sermons has been named the mastermind behind the devastating Sri Lanka terror attacks, it was claimed Tuesday.
Sri Lankan intelligence has named local cleric Moulvi Zahran Hashim as being behind the coordinated suicide bombings on churches and hotels that killed at least 321 on Easter Sunday, according to The Telegraph.
He was already eyed for gaining thousands of online followers for hateful online sermons — some using the World Trade Center attacks as a backdrop, according to the report.
His name emerged in warnings earlier in April that radicals were planning attacks in the capital Colombo — weeks before the suicide bombings that, according to the report.