The massive cross-Border security operation launched yesterday against an oil laundering business will resume along the Louth-Armagh border this morning.
Gardaí believe the main focus of the inquiry, former chief of staff of the IRA Thomas "Slab" Murphy, may have hidden from them in an underground bunker throughout the day.
Today's follow-up operations will have to deal with the disposal of up to six tonnes of synthetic chemicals believed to have been used in the oil laundering business and which may be highly toxic.
Murphy was not at home when his farm straddling the Border at Ballybinaby in north Louth was raided just before 7am yesterday.
Three people aged in their 50s and 60s, two men and a woman, were arrested during yesterday's operation. All were later released.
Yesterday's searches of multiple sites and premises, named Operation Achilles, involved more than 300 Garda and PSNI officers, Irish and British soldiers, and customs and revenue officials from both sides of the Border.
Co-ordinated searches took place around the townland of Ballybinaby and across the Border in Crossmaglen, south Armagh, and in Newry, Co Down.
The operation was linked to the investigation last year into a €44 million property empire around the Manchester area with which Murphy has been linked.
A fleet of tankers which were being used to transport laundered fuel was seized during the searches. Some of the trucks bore the livery of multinational fuel companies, allowing them to drive cross-country without arousing suspicion.
Four laundering facilities attached to a major network of storage tanks, some of which were underground, were also found.
Gardaí also recovered at least €200,000 in cash stuffed into plastic bags, 30,000 smuggled cigarettes and two firearms.
Documentation and computer hard drives were also seized at the north Louth properties and at a number of offices in Dundalk and Crossmaglen.
Gardaí believe a soft-sided trailer fitted with large oil tanks has been used to export oil off the island of Ireland by truck via the ports.
The Irish Times has learned that a very significant amount of illegal fuel has been detected leaving Dublin Port destined for Liverpool for distribution across northern England. One line of inquiry now being pursued is that at least some of this fuel came from the plant targeted yesterday.
The three people who were arrested were taken for questioning to Garda stations in Drogheda and Kells. They were released without charge last night. A file will be prepared for the Director of Public Prosecutions.
A fourth person escaped during the course of the raids in north Louth. He drove away at high speed across the Border into Northern Ireland and then took to the fields on foot.
He is a much younger man than the people who were arrested and is well known to them.
The Garda helicopter was involved in trying to follow him and is believed to have briefly entered Northern airspace.
Gardaí said a break-in at Dundalk courthouse where the search warrants used yesterday were issued on Wednesday was in no way linked to the operation.
Yesterday's searches in the Republic were carried out by up to 150 personnel from the Garda, revenue, customs and Army.
A similar number of PSNI members, British soldiers and customs personnel were involved in searches north of the Border in Crossmaglen, Co Armagh, and Newry, Co Down.
