Crossword Clue:

Inform on

AnswerCrossword Clue
TATTLEInform on.
BLOWTHEWHISTLEInform (on)
RATInform (on)
RATInform on
LET... in on (inform)
RATOUTInform on, slangily
RATInform on, with "out"
RATInform on the Mob
RATInform on the mob
SINGInform on a fellow-criminal: Slang.
SINGInform on partners in crime: Slang.