Four people questioned about an attempted car bomb attack on a policeman have been released.
The booby trap device was left under the officer's car at his home near Eglinton, Derry, in June 2015.
The targeted man's wife was also a serving PSNI officer.
Three men, aged 29, 38 and 46, and a 32-year-old woman were detained on Thursday. The arrests were undertaken in Belfast, Derry and Pomeroy.
The suspects, who were questioned at Musgrave police station in Belfast, have been released without charge.
