The hunt at O'Neill's former boarding house in Hammersmith, west London, took place as Sinn Fein claimed that police had fired on an unarmed man. Scotland Yard refused to comment, saying: "It is part of a Police Complaints Authority inquiry now."
The parents of Mr O'Neill, who was born and lived in London, left home in the Irish Republic yesterday to identify their son's body. Their other son, Shane, 23, is understood to be among the five men arrested in the raids on Monday.
All of the suspects were still being questioned yesterday at Paddington Green police station. Armed officers carried out raids at four addresses and recovered a vast amount of home-made explosives, two lorries, car booby traps, and guns at a north London warehouse.
Mr O'Neill was born and lived in London. Like his brother Shane, he went to London Oratory School in south-west London. John McIntosh, the headmaster of the school, whose pupils include Tony Blair's son, Euan, said both boys were "well-behaved and pleasant".
There are reports that Dermot was sentenced to 12 months in a young offenders' centre after being convicted of fraud and deception charges in 1988. The offences were linked to the Shepherds Bush branch of the Bank of Ireland involving a sum of pounds 75,000, a part of which was reportedly channelled to the IRA.
Mr O'Neill's parents, Eoghan and Teresa, moved to Ireland from London two years ago when they retired. Mr O'Neill originates from Co Cork and his wife from Dublin. They also have two daughters. A local resident, Charlie Madden, a publican, said: "I'm shocked. This was a lovely lad who came home to see his father a couple of times a year." He added that the family never spoke about, nor got involved in, politics.
Nevertheless, it emerged last night that the dead man sold copies of the republican newspaper An Phoblacht when he was 16 or 17-years-old, and may have been recruited by the IRA at that stage.
The other four men being questioned are Brian McHugh, James Murphy, Patrick Kelly and Michael Phillips, a 21-year-old, newly qualified engineer working at Gatwick airport. Anti-terrorist officers continued a detailed search of the three London properties and another property in Crawley, Sussex.
Early yesterday, the Irish police also carried out raids on homes in Co Monaghan and in Co Longford. The moves were linked to the London operation but no one was arrested.
The IRA's apparent intention to carry out more bombings has hardened Unionist determination that the issue of decommissioning terrorist weapons must be dealt with at the top of the multi-party talks agenda.Reuse content