NSW Ombudsman Bruce Barbour says he questioned Deputy Police Commissioner Catherine Burn for four days as part of his long-running investigation into a phone-tapping scandal.
And Mr Barbour has dismissed critics, saying he has not targeted whistleblowers, including police officers who complained about being improperly bugged by rival officers in the force.
Mr Barbour appeared before a NSW parliamentary inquiry on Tuesday to defend Operation Prospect, his two-year probe into claims illegal warrants were used to bug more than 100 police officers in an anti-corruption probe 15 years ago.
The ombudsman's appearance follows an extraordinary attack from Deputy Commissioner Nick Kaldas, who last week accused Mr Barbour of denigrating and humiliating him during questioning.
Mr Kaldas, who was bugged during Operation Mascot, said Mr Barbour was more interested in how targeted officers acquired leaked information about the warrants than investigating the complaints themselves.
Mr Barbour said Mr Kaldas had failed to appreciate how he was conducting his investigation.
Mr Kaldas had been questioned for one day, he said, while Commissioner Burn was questioned for four days.
"These raw figures are sufficient to indicate the primary focus of the inquiry," Mr Barbour said.
Ms Burn was the team leader of Operation Mascot, the 2000 police internal affairs surveillance operation at the heart of the complaints.
"To suggest that my inquiry is focused on targeting whistleblowers is quite simply false," Mr Barbour said.
Mr Barbour told the Upper House committee that he had not asked complainants many questions about the buggings because they would not know how decisions were made to issue warrants.
Ms Burn, who appeared before the inquiry last week, has denied any wrongdoing and said she had suspicions when her team sought a warrant to bug Mr Kaldas's phone.
Mr Barbour has warned the parliamentary inquiry that the four-day public hearing could make his investigation, which has been conducted in secret, impossible.
The hearing continues.
