A man in his 20s is being questioned over the murder of Detective Adrian Donohoe.
He was arrested outside Wheatfield prison yesterday after he finished a jail sentence for traffic offences.
The arrest follows a major investigation into the death of Adrian Donohoe who was shot dead during a raid on the Lordship Credit Union in January 2013.
Speaking on the fifth anniversary of his death last month, Chief Superintendent Christopher Mangan, appealed for information.
He said: “Persons involved in this murder have, no doubt, received logistical and emotional support from their families and friends.
“I am speaking to you in particular, the families and friends of these people who are involved in the murder, your mind will never have peace until you tell the truth of what happened to Adrian. It’s not too late to do the right thing.”