The Investigatory Powers Tribunal (IPT) is probing revelations that the phone records of a respected Belfast-based journalist were secretly searched by the PSNI.
In a separate case in December last year, the PSNI settled a case before a public hearing of the IPT was about to start. This related to a case involving former PSNI men Mark Gilmore and Duncan McCausland.
Former Assistant Chief Constable McCausland was at the centre of a 2014 bribery investigation by the PSNI.
The probe into multi-million-pound vehicle contracts led to officers being arrested or suspended.
Mr McCausland always denied the charges against him and the case collapsed without criminal charges.
Eight people were arrested and questioned in connection with the case, including retired ACC McCausland and a serving PSNI officer.
The then Chief Constable of West Yorkshire Police Mark Gilmore was also suspended.
Mr McCausland and Mr Gilmore later complained to the Investigatory Powers Tribunal about secret surveillance in the case and in December 2022, the PSNI settled the case just before a public hearing was about to start, admitting it had broken its own intelligence rules.
The investigation involved secret surveillance, including the interception of personal phone calls by Mr Gilmore.
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An employee of Newforge Country Club in Belfast claimed he was asked by police to spy on Mr McCausland and Mr Gilmore.
There are strict rules regulating the use of intelligence sources that require police to review members of the public who provide them with information more than three times.
In 2022 the PSNI conceded this did not happen in the case of the Newforge source.
