All 3 Uses

inconclusive
in
Nineteen Minutes
(Edited)

Gun B had a partial print on it that was inconclusive.
Chpt 1

inconclusive = not conclusive (not putting an end to doubt or question about whose print it was)
There's an inconclusive print on the trigger, probably smudged when your suspect dropped it, but I can't say that for certain.
Chpt 1
He had spent hours at the police station, his first stop after leaving Alex's house, scrutinizing the enlarged fingerprint that had been on Gun B. An inconclusive one; one that he'd assumed, lazily, to be Peter's.
Chpt 2 *

Definitions:

(1) (inconclusive)
not conclusive (not putting an end to doubt or question)

Standard prefix: in- at the beginning of a word often means "not" as in incorrect or independent. So, inconclusive means not conclusive.
(2) (meaning too rare to warrant focus)