One of the bombers in the Sri Lanka terror attacks studied in the UK and Australia before returning to the Indian Ocean island, a government minister says.
Sri Lankan officials have not named the bomber who studied in Britain or identified the university where he obtained an undergraduate degree.
The terrorists were mostly well-educated, and from the country's middle and upper middle classes.
State Minister of Defence Ruwan Wijewardene told reporters: "We believe that one of the suicide bombers studied in the UK and later did his postgraduate studies in Australia."
Meanwhile a government minister claims top intelligence officials deliberately hid information received before the bombings, and top security officials failed to act on several warnings of possible attacks over Easter.
Sri Lanka: 'Family of hate' behind terror attacks are wealthy brothers and wife
Officials said there were nine suicide bombers who detonated explosives - raising the total from seven - and confirmed one of them was a woman.
ISIS has claimed responsibility for the blasts at hotels and churches which have so far killed at least 359 people, the deadliest attack ever in south Asia and likely the deadliest ever linked to the terror group.
Eight of the nine bombers have been identified, officials said on Wednesday as the death toll increased again.
It has emerged Sri Lanka: 'Family of hate' behind terror attacks are wealthy brothers and wife - a husband and wife, and the man's brother-in-law.
Sri Lanka attacks: Mum set bomb off killing children as police raided suspect's home
Sri Lanka attacks: Mum set bomb off killing children as police raided suspect's home killing her three children, as police raided the couple's luxury flat after her terrorist husband killed guests at a hotel.
At least 39 of the victims were foreigners, including eight from Britain.
Lakshman Kiriella, Sri Lanka's leader of parliament and minister of public enterprise, claims senior officials deliberately withheld intelligence about possible attacks.
He told parliament: "Some top intelligence officials hid the intelligence information purposefully.
"Information was there, but the top brass security officials did not take appropriate actions."
He said information on possible suicide attacks on churches, hotels and politicians were received from Indian intelligence on April 4 and a Security Council meeting was chaired by President Maithripala Sirisena on April 7, but the information was not shared more widely.
He added: "Somebody is controlling these top intelligence officials. The Security Council is doing politics. We need to investigate into this."
Sarath Fonseka, former army chief and minister of regional development, told parliament he believed the attacks "must have been planned for at least seven to eight years."
His statement came a day after Mr Wijewardene said the initial investigation found that the attacks were carried out in revenge for last month's mosque shootings in New Zealand.
Sri Lanka remains on high alert with the country under a state of emergency and an overnight curfew.
There were further scares on Wednesday as security forces carried out a controlled explosion on a suspicious bag at a restaurant in Katana, and another on a suspicious motorbike parked near the Savoy cinema in Colombo, local media reported.
No explosives were found on the motorbike, and it did not pose a threat after all.
On Tuesday, the national police force revealed it was hunting a lorry and a van believed to be packed with explosives.
The US ambassador to Colombo, Alaina Teplitz, believes terrorists in Sri Lanka are plotting more attacks.
The envoy said there were failures in Sri Lanka for the warnings to be missed, and the US had no prior knowledge of the bombings.
She added: "We believe there are ongoing terrorist plots. Terrorists can strike without warning. Typical venues are large gatherings, public spaces."
British counter-terror experts and agents from the FBI and Interpol are assisting Sri Lankan investigators.
More than 60 people have been arrested since the Easter Sunday bombings, and more than 100 are likely to be detained, said Mr Kiriella.
