Anderson acknowledged the “professionalism and commitment” by investigators in the National Integrity Unit.
“Our investigations have involved the analysis of a significant volume of web activity.
“It is important we now let these matters progress to the court process, which limits the level of information we can provide at this point.”
The three police staff remain stood down from duties, while three investigations remain ongoing as part of the rapid review.
Police have investigated 22 cases in this matter, Anderson said.
Twelve cases have been resolved through either disciplinary action or performance management.
Four people have resigned during the process.
It comes after McSkimming, who served as Deputy Police Commissioner from 2020 until his resignation last year, was convicted for possessing child sexual exploitation and bestiality material, including on his work devices.
The investigation into McSkimming prompted a “rapid review” of police’s information security (Infosec) controls.