Not much on the Cape for FBI Joe. Try 167.6625 for the only known site [Barnstable]
But you are best to SEARCH the 162-174 Band, between 8-10am, Boston [Central] does Roll Call with the RA's.
SouthEastern Mass has been converted to P25, some of the Boston traffic is a mix P25/167.9 Hz and the Merr Valley is still Analog and very active.
Can anybody help with the frequencies that the FBI uses in Massachusetts ?