DavidKotelchuck.net
RP 25 FBI Suspends Hatch Act Investigation

Text on page 25:

But the government was apparently in its own bind. Arguably it could not fire the five under the Hatch Act if they were members of the CPA and not the CPUSA — indeed, Hoover instructed the special agent in charge of the Baltimore office of the FBI “that the usual Hatch Act investigation not be conducted.”

Copy of original memo: