Personally, I think this should be part of the duties of the Office of the Inspector General, and the OIG should be shunted to being answerable to the either the Legislature, or the Courts.
Of course, I also believe that OIG should be hounding the Executive constantly, and have the authority and onus to declassify anything classified as soon as possible too. That means that classification stops being a privilege of the Executive, and instead becomes a maintenance item That requires periodic review to reclassify.
I believe you are correct in that the spirit is SOME official watchdog should exist within the government. Even better some department for EACH BRANCH.
However it is also commonly said that a "fourth estate" (or branch) exists, and the top search result that I get for that phrase is:
"What is the role of the Fourth Estate?
In the United States, the term fourth estate is sometimes used to place the press alongside the three branches of government: legislative, executive and judicial. The fourth estate refers to the watchdog role of the press, one that is important to a functioning democracy.Jan 3, 2019
The press should also watch the government, and the oversight branches, and all of them should have oversight over the others as a completely closed system that roots out any actions that are may represent impropriety, immoral, OR illegal actions.
Of course, I also believe that OIG should be hounding the Executive constantly, and have the authority and onus to declassify anything classified as soon as possible too. That means that classification stops being a privilege of the Executive, and instead becomes a maintenance item That requires periodic review to reclassify.