english
1
general::
Phrase(s): put the finger on someone [and] lay the finger on someone Sl. to accuse someone; to identify someone as the one who did something. • Tom put the finger on John, and John is really mad. • He’d better not lay the finger on me. I didn’t do it.
McGrawhill's American Idioms And Phrasal Verbs
2
general::
Inform on, as in The witness put the finger on the defendant. [Slang; c. 1920] Also see PUT ONE'S FINGER ON.
American Heritage Idioms