On the morning of 31 July 1972, three car bombs exploded in the centre of Claudy, a village in County Londonderry, Northern Ireland, killing nine civilians and injuring thirty others. The attack became known as "Bloody Monday." Those responsible had attempted to send a warning ahead of the explosions, but the warning was delayed because local telephones were out of order following an earlier bomb attack on the telephone exchange. The first bomb, hidden in a stolen Ford Cortina, detonated outside a pub and shop on Main Street. A second bomb outside the post office on Main Street was spotted by a police officer, who directed people toward Church Street, where a third bomb then exploded outside a hotel, killing three people who had already been injured by the first blast. The bombing occurred hours after the British Army began Operation Motorman, an operation to reclaim areas of Belfast and Derry controlled by Irish republican paramilitaries.
The Provisional IRA denied responsibility for the attack at the time and later said an internal inquiry had cleared its local unit. However, in December 2002, following a review of intelligence material, it was revealed that the IRA had in fact been responsible for the bombings. Derry politician Ivan Cooper stated that he had been told, within days of the bombing, that the IRA was behind it, and said he later became convinced that Fr James Chesney, a Catholic priest, was involved.
A Royal Ulster Constabulary (RUC) investigation at the time identified a suspect whose car matched a vehicle used by those attempting to give the bomb warning; this suspect provided an alibi corroborated by Chesney. When Chesney's car was later stopped at a checkpoint, a sniffer dog detected traces of explosives. Investigating officers came to suspect that the alibi had been prearranged and that Chesney served as quartermaster and director of operations for the IRA's South Derry Brigade. Chesney was questioned informally by two successive Bishops of Derry and denied involvement both times. He was never arrested or formally interviewed by police, and was later transferred to a parish in County Donegal. He died in 1980.
A PSNI investigation launched in 2002 uncovered documents showing that the Secretary of State for Northern Ireland had discussed Chesney's suspected involvement with the head of the Catholic Church in Ireland. In 2005, PSNI detained four people, including a Sinn Féin politician, in connection with the bombing; all were released without charge the next day.
On 24 August 2010, the Police Ombudsman for Northern Ireland published a report concluding that senior RUC officers, government ministers and the Catholic hierarchy had colluded to remove Chesney from Northern Ireland rather than pursue his arrest, in order to avoid destabilising the security situation. The report found this decision had failed the victims, their families, and the investigating officers. A memorial to those killed and injured was erected on Claudy's Main Street in 2000.