At least 400 soldiers and officers from the Garda Siochana, the Republic of Ireland's national police, and the Police Service of Northern Ireland raided several properties in the so-called "bandit country" borderland. Among the first properties targeted was Murphy's border-straddling farm. Police reported no immediate arrests.
An anti-racketeering detective, speaking to The Associated Press on condition he not be named, said the operation was in part a follow-up trawl for documention of IRA money-laundering.
The detective said the raids were conducted in the hope of identifying links to a portfolio of properties in Manchester, northwest England, that were frozen last September on the suspicion they had been purchased with IRA proceeds. One of Murphy's brothers has acknowledged he owns some of those properties but denies any link to the IRA.
Thomas Murphy has never been convicted of any crime, but anti-terrorist police and several published histories of the IRA identify him as the outlawed group's longtime chief of staff.
In 1985, London's Sunday Times newspaper published an investigation of Murphy that identified him as a millionaire smuggler and a pivotal figure in plotting bomb attacks. Murphy sued for libel but lost twice. In 1998, a Dublin jury ruled he was an IRA commander and a smuggler.