If any of the people he ran popped a warrant, then there is a good chance there would be a record of that search. NY State has such a system in place. Its purpose is to alert the agency that issued the warrant or has interest in the person (criminal court, parole officer, another PD, etc.) that someone is investigating their suspect. That way, the original agency can immediately contact the investigator who ideally has the person he is investigating in custody.
The NYPD is constantly firing civilians who use the warrant search system to check on the backgrounds of their new boyfriends/girlfriends. The firing results when the boyfriend/girlfriend pops a warrant, a department alert is auto-generated and then the Department learns that nobody was arrested to satisfy the warrant check. A nice system of checks and balances to prevent abuse. Most PDs do not operate on that level.