BELFAST (Reuters) - Northern Irish police said on Sunday they had set up a special task force to hunt down and find those responsible for the devastating car bomb which killed at least 28 people in the town of Omagh on Saturday. "No stone will be left unturned until we bring these people to justice," Royal Ulster Constabulary chief Ronnie Flanagan said. Flanagan said the task force would be headed by one of his deputies. It would concentrate its investigations on a dissident republican guerrilla group known as the Real IRA which opposes efforts to bring peace to the troubled province. "It`s fair to say our focus at this point in time would be on those that call themselves the 32-County Sovereignty Movement and those close to them," he told BBC television. "They are out to murder people for the sake of murdering people. That`s exactly what they did yesterday." The 32-county movement is led by republican hardliners and has launched a challenge at the United Nations to Britain`s right to rule the six counties of Northern Ireland. It denies a widely held perception in the Irish Republic that it is the political wing of the Real IRA. The mainstream IRA, or Irish Republican Army, has declared a ceasefire as part of the peace process but the Real IRA and two other small dissident republican groups - the Continuity IRA and the Irish National Liberation Army - have vowed to continue their violent struggle to oust Britain from Northern Ireland. Flanagan also reiterated that the telephone warning given to police ahead of Saturday afternoon`s blast appeared to have been deliberately misleading. Police said the caller told them a bomb had been left in a car near the town`s courthouse. They moved people away from the courthouse - right into the area where the bomb actually exploded.