If you're in the immediate area of these operations you need to be monitoring their comms.
Since exact frequencies are unknown, but bands are known, you should perform a band search.

The following bands are of primary interest:

30-88 MHz. Pay particular attention to:
30-30.55 MHz.
32-33 MHz.
34-35 MHz.
36-37 MHz.
38-39 MHz.
40-42 MHz.
46.5-47 MHz.
49.5-50 MHz.
138-144 MHz.
148-150.775 MHz.
225-400 MHz.

The following bands are of secondary interest:

118-138 MHz.
162-174 MHz.
400-420 MHz.

Extensive use of P25 and FHSS is expected. Real Frequency Hopping Spread Spectrum. Police scanners with P25 capability and RTL-SDRs will be necessary.