The New IRA is being blamed for the bomb planted under a police officer's car in east Belfast.
The viable device was placed under his vehicle in the Shandon Golf Club on Saturday afternoon.
A cross-border investigation is under way into the incident.
While no one has claimed responsibility, Sunday Times investigative journalist John Mooney believes it was planted by dissident republicans.
He says the group merged in 2012 and have grown ever since.
John Mooney says its members are long standing Republicans who have walked away from the mainstream movement.