One of the Sri Lanka suicide bombers studied in the UK, police in the country said, as they announced the death toll has risen to 359 and more than 58 arrests have been made.
Sources say he is Abdul Lathief Jameel Mohamed.
In addition to those who lost their lives, more than 500 people were wounded when seven suicide bombers targeted three churches and three luxury hotels, as well as three related blasts, on Easter Sunday.
Eight Britons were killed in the attacks, and the identity of the eighth victim was reported on Wednesday.
Sri Lanka's Prime Minister Ranil Wickremesinghe has today called for the resignations of the country's defence secretary and national police chief following the Easter bombings.
Despite so-called Islamic State claiming responsibility for the attacks and releasing images that purport to show the bombers, Sri Lankan authorities say they have not yet determined whether the atrocities were were directed or inspired by the terror group.
Speaking on Wednesday, Sri Lanka's Defence Minister Ruwan Wijewardenesaid the bombers' association with so-called IS was “through ideology, maybe funding”.
ITV News Security Editor Rohit Kachroo said the minister's comments appeared to confirm a link to so-called IS "meaning that 29 days after territorial defeat was declared in Syria, it managed to launch or inspire its deadliest ever attack outside the Middle East - with a death toll for larger than Paris in a country where it had only a small footprint".
Sri Lankan authorities have blamed a local extremist group, National Towheed Jamaar (NTJ) - who previously had only defaced Buddhist statues - for the attack, but they have not claimed responsibility.
The Defence Minister also told the briefing that all of the attackers were all middle-class Sri Lankans with money and an education, adding that one of them had studies in the UK before studying in Australia.
Sri Lankan Prime Minister Ranil Wickremesinghe said investigators were still working to determine the extent of the bombers’ foreign links.
Mr Wijewardene said the Government had evidence that the bombings were carried out “by an Islamic fundamentalist group” in retaliation for the March 15 mosque shootings in New Zealand, that killed 50 people, although he did not disclose what the evidence was.
New Zealand's Prime Minister Jacinda Ardern has said she has not received any official advice from Sri Lanka or seen any intelligence reports to corroborate claims from the Government that the attacks were in retaliation for the mosque massacres in Christchurch.
So-called IS’s Aamaq news agency released an image purported to show the leader of the attackers, standing amid seven others whose faces are covered.
The group did not provide any other evidence for its claim, and the identities of those depicted in the image were not independently verified.
On Tuesday, Mr Wickremesinghe warned that several suspects armed with explosives were still at large.
Addressing Parliament on Wednesday, Mr also said “weakness” within Sri Lanka’s security apparatus led to the failure to prevent the nine bombings.
“By now it has been established that the intelligence units were aware of this attack and a group of responsible people were informed about the impending attack,” Mr Wijewardene said.
“However, this information has been circulated among only a few officials.”
In a live address to the nation Sri Lanka’s president, Maithripala Sirisena, said he also was kept in the dark on the intelligence about the planned attacks.
Neither the President, Prime Minister or his Cabinet are said to have been informed of information suggesting attacks were planned, exposing continuing turmoil in Sri Lanka’s government.
Mr Sirisena vowed to “take stern action” against the officials who failed to share the information and also pledged “a complete restructuring” of the security forces.
It also emerged on Wednesday that the FBI was on the ground in Sri Lanka to help assist the investigation.
Meanwhile specialist officers from the UK’s Metropolitan Police’s Counter Terrorism Command have been sent to the country to support the bereaved.
A block on most social media in Sri Lanka since the attacks has left a vacuum of information, fuelling confusion and giving little reassurance the danger had passed.
Mr Wickremesinghe said he feared the massacre could unleash instability and he vowed to “vest all necessary powers with the defence forces” to act against those responsible.
The history of Buddhist-majority Sri Lanka, a country of 21 million including large Hindu, Muslim and Christian minorities, is rife with ethnic and sectarian conflict.
But Sri Lanka has no history of Islamic militancy. Its small Christian community has seen only scattered incidents of harassment.
The Easter Sunday attacks were the worst violence the South Asian island nation had seen since its civil war ended a decade ago.
Among the British victims were Anita Nicholson, her son Alex, 14, and daughter Annabel, 11, who died when one of seven suicide bombers struck as they ate breakfast at the Shangri-La hotel in Colombo.
Londoner Matthew Linsey’s daughter Amelie, 15, and son Daniel, 19, were killed in the same blast on the final day of their holiday.
GP Sally Bradley and her husband Bill Harrop, a retired firefighter, from Manchester, died in the Cinnamon Grand Hotel bombing.
The eighth victim is reported to be Lorraine Campbell, 55, from Manchester, with the Daily Mail saying she was staying at the Cinnamon Grand Hotel on a business trip.
Her son Mark told the paper: “I have been told it is her. She has been taken in a terrible way.”