Police investigating the murder of prison officer David Black have made another arrest.
The married father of two was gunned down in a high-speed motorway ambush last Thursday as he drove to work at Maghaberry prison in Co Antrim.
On Tuesday, Mr Black's family denounced his killers as cowards during his funeral in Cookstown, Co Tyrone.
A Police Service of Northern Ireland spokesman said: "Detectives investigating the murder of David Black on the M1 motorway on Thursday November 1 have arrested a 46-year-old man in the Lurgan area." He has been taken to Antrim police station for questioning.
Three men, two in Northern Ireland and one in the Republic of Ireland, have been questioned and released by police.
Mr Black, 52, was killed by suspected dissident republicans, police believe. He is the first prison warder murdered by paramilitaries in Northern Ireland in 20 years.
Gunmen travelling in a stolen car fired on the victim's Audi near a junction leading to Portadown, Co Armagh, as he was on his way to Maghaberry. The vehicle careered off the road and into a ditch.
At Tueday's funeral at Molesworth Presbyterian Church in Cookstown, Mr Black's daughter Kyra, 17, paid tribute to her "special hero". His cousin and lifelong friend Jim Slaine said he hoped the perpetrators would get what they deserved.
Head of the Presbyterian Church in Ireland Roy Patton vowed that the efforts of the gunmen to drag Northern Ireland backwards would not work. Smartly-uniformed prison officers carried the coffin to the church in military fashion behind a Scottish bagpiper who played a lament.
Stormont First Minister Peter Robinson, Police Service of Northern Ireland chief constable Matt Baggott and justice ministers north and south of the Irish border attended the funeral in Co Tyrone.