SSDD
The DOD (not the DOJ) is the agency undergirding all things relating to the COVID-19 Vexxationation (i.e., the Not-A-Vax).
Wouldn’t be surprised to learn that the DOD is the agency behind this Big Brother-style domestic civilian location monitoring program.
The DOJ, headed by the Attorney General, is probably NOT the undergirding agency because of certain restrictions it operates under with respect to domestic spying on civilians/citizens. Plus, IIRC, ordinary citizens can request to review the contents of any open or closed file the FBI or DOJ has on them.
Similarly, the CIA, organized under the Office of the Director of National Intelligence (ODNI), another cabinet-level government official, is probably not behind this. Its focus is overseas. Plus the domestic restrictions that limit what the DOJ/FBI can do also limit the CIA.
As long as the President according to current law sets the right national security or defense condition to expand the DOD’s freedom of action, one can easily imagine that any given official or investigator at the DOD will not consider himself or herself restricted in any way in terms of treating civilians like chattel slaves or livestock.