"In U.S. criminal law, means, motive, and opportunity is
a common summation of the three aspects of a crime
that must be established before guilt can be determined
in a criminal proceeding." — Wikipedia
See also "Motive for Metaphor" in this journal.
"I'm in with the in crowd,
I go where the in crowd goes"
— Musical motif of the recent film "Irrational Man"