David Black murder - 'Very sad day for prison service'
The prison officer shot dead on the MI in Northern Ireland was David Black, a married father of two, from Cookstown.
Mr Black, 52, was attacked on the motorway between Portadown and Lurgan at about 07:30 GMT as he drove to work at Maghaberry Prison, County Antrim.
A car with Dublin registration plates drove up beside him and fired a number of shots. His car veered into a ditch.
Assistant Chief Constable Drew Harris said he sustained very serious and probably fatal gunshot wounds.
PSNI Chief Constable Matt Baggott and the head of the Northern Ireland Prison Service Sue McAllister condemned the murder at a press conference earlier.