zero in on
Verb
to zero in on (someone or something)
1. (idiomatic) To aim precisely at a target
● The pilot zeroed in on the bunker and launched a guided missile.
2. To successfully narrow down a search
● We have zeroed in on the source of the problem.
● See if you can zero in on the caller.
3. To concentrate or focus one's attention on at task
● One member of the check fraud team will zero in on the fingerprints.
4. To converge on something
● At the spring sale, everyone zeroed in on the bargain clothes.