The suspects would allegedly look for envelopes that may have contained cash, checks or gift cards, then smuggle them out of the state's main distribution center.
Federal investigators have broken up a "well-organized and wide-ranging conspiracy" to steal valuables from the mail in Rhode Island and Massachusetts, they announced.
Five fallen firefighters, including former Maroa Fire Chief Larry Peasley, were honored for their sacrifice, while several others were recognized for going above and beyond the call of duty.