A man is due to appear in court today charged in connection with the murder of a prison officer in Co Armagh in 2012.
David Black (52) was shot dead as he drove to work along the M1 motorway in November 2012.
The father-of-two was the 31st member of the prison service to be killed in the North, the first such murder in almost 20 years.
Detectives arrested a 33-year-old man in Lurgan in Co Armagh on Monday. The man also faces charges of possessing a firearm with the intent to endanger life.
The accused will appear at Craigavon Magistrates' Court today, a Police Service of Northern Ireland (PSNI) spokeswoman said.
Mr Black, from Cookstown in Co Tyrone, was on the M1 motorway enroute to Maghaberry Prison in Co Antrim when he was shot at high speed.
The Toyota Camry car used in his killing was later found burnt out in Lurgan.
Two other men, on either side of the bortder, face charges linked to the purchase and movement of the Toyota Camry.
A PSNI spokeswoman said the force wanted to thank An Garda Síochána for their help and support throughout a "difficult and complex" investigation spanning both sides of the border.