After the Day of Chaos incident, the Justice Department decided that the three investigative and intelligence-gathering units (the Wally Squad, the Special Judicial Squad and the Public Surveillance Unit) should be reorganized under one Division. This would place all the operations under one roof - eliminating duplication of effort, the hoarding of needed information, and jealous infighting between the units.
This reorganization would allow the use of assets between units to improve efficiency. Each unit by itself previously had a tribalistic need to assert control over a case and keep it "in house" to insure that when it was solved that the credit went to them. The new system would reward cooperation and efficiency instead.
It would also take the core competencies of each unit to round out investigations and make them more thorough. Each unit has its own method of investigation and obtaining information. A detachment made up of Judges from different units would bring their unique strengths to the task. PSU Judges know how to sort through collected raw surveillance data and are observant and patient, Wally Squad Judges have civilian sources and contacts in addition to their interpersonal skills, and SJS Judges have a mixture of curiosity, intuition, and paranoia to sniff out corruption.
The downside is that the heads of these units have famously imperiled the City in the past. The infamous mad Judge Cal was the head of the SJS and the power-hungry Judge Edgar was head of the PSU. Now all the power of these three key units would be under the control of one Judge and the checks and balances of inter-unit rivalry would be eliminated.