DUBLIN A second man was arrested on Tuesday in connection with the killing of Catholic police officer Ronan Kerr in Northern Ireland, police said.
Kerr was killed by a bomb that exploded under his car as he drove to work from his home in Omagh in April 2011. It was the first murder of a policeman in the British-controlled province for two years.
A 39-year-old man from Omagh was detained on Tuesday for questioning about offences linked to the murder, the Police Service of Northern Ireland (PSNI) said.
A day earlier, a 22-year old man, also from Omagh, was arrested in the English town of Milton Keynes and was still being interrogated, officers said.
Kerr's murder was claimed by the Continuity IRA, a group of militant Irish nationalists opposed to a 1998 peace deal that largely ended more than three decades of violence between Protestants loyal to British rule and mostly Roman Catholic nationalists who want to unite with the Ireland.
The young Catholic was targeted as a symbol of the reorganisation of the police service, which had been almost exclusively Protestant before the peace deal. No one has been charged over the killing.
In the wake of Kerr's death, police in Northern Ireland said the threat from dissident militants was at its highest level since the peace deal.
The arrests came at the end of a month which saw a prison officer, David Black, shot dead by a dissident republican grouping as he drove to work at the top security prison along Northern Ireland's main motorway.