A suicide bomber reportedly educated in the UK and involved in the Sri Lanka terror attacks was radicalised after leaving Britain, his sister has said.

Abdul Lathief Jameel Mohamed is understood to have studied in the south-east of England between 2006 and 2007 - later completing a postgraduate course in Australia.

His sister Samsul Hidaya told MailOnline: "My brother became deeply, deeply religious while he was in Australia... he came back to Sri Lanka a different man.

"He had a long beard and had lost his sense of humour."

She told the news site he ended up "really angry and totally crazy", and admonished male relatives who shaved their beards.

Eight Britons were among at least 359 people killed by a series of coordinated blasts at three churches and three hotels on Easter Sunday, with hundreds more wounded.

Mohamed is reported to have studied aerospace engineering at Kingston University in south-west London, but the university said it could not confirm this on Thursday.

The identity of Mohamed was first reported by Sky News, which said he was in the UK between January 2006 and September 2007, before returning to the UK in 2008 for a period.

Sri Lankan authorities have said there were nine suicide bombers, two of whom were the sons of a wealthy spice trader, according to media reports.

The father of the pair was reportedly arrested on suspicion of aiding his sons on Thursday.

Many of the attackers came from well-educated, middle-class families, and had been part of a pair of little-known extremist Muslim groups, Sri Lanka's junior defence minister Ruwan Wijewardene told reporters.

Police in Sri Lankan capital Colombo have detained 58 people in connection with the bombings, claimed by the Islamic State group.

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.

IT specialist Lorraine Campbell, 55, was also in the Cinnamon Grand on a work trip when she was killed.

Her husband Neil Evans said: "Lorraine was a real tour de force. She epitomised the qualities she lived by, and was a conduit for bringing people together to both make things happen, and make them better.

"I've lost my best friend in the world for all the adventures we shared and planned for the future."

Juno Srivastava, a student at Middlesex University Dubai campus, also died in the blasts, while a locally employed British Council worker was said to be in hospital with his wife, both seriously injured.

Specialist officers from the Metropolitan Police's Counter Terrorism Command have been sent to the country to support the bereaved and Scotland Yard has asked for images or video taken during the attacks.

By Thomas Hornall