finger as

finger (one) as (someone)

To identify someone as having had a particular role in something. If they have security cameras, they'll definitely be able to finger us as the thieves!
See also: finger
Farlex Dictionary of Idioms. © 2022 Farlex, Inc, all rights reserved.

finger someone as someone

Sl. to identify someone as a certain person. (As if one were pointing a finger at someone.) Max fingered his partner as the gunman. The accountant fingered the bookkeeper as the one who fixed the books.
See also: finger
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
See also:
References in classic literature ?
He tried it on his left hand; it fit his finger as if made for it.
"I wonder whether it would condescend to alight on such a great clumsy finger as mine?
Move the right hand little finger as you say, "Mooooo."
Children with a ring finger as long as their index finger were better with numbers, while those with a shorter ring finger proved to be more adept at literacy exams.
For instance, he wonders whether, if two rods were placed on a finger as researchers somehow induced the illusion that the finger was expanding, the perceived distance between the rods would expand proportionately.
Address large stretches between the thumb and fifth finger as well as stretches between inner fingers of the hand, such as full first inversion chords and seventh chords.