Boyfriend was adopted in the 70's, looking for info on bio-dad who was a Cheviot cop?

Hello r/Cincinnati! Like the title says, my boyfriend recently got in touch with his birth mother (and she's wonderful by the way!), who gave us what information she could about his biological father. We know that he has since passed, but boyfriend is still really interested in learning what he can about his father. I've tried looking through dozens of different local newspaper archives and public records with limited results. I'm kinda leery of posting any identifying details for obvious reasons, but if anybody knows how I could go about looking for information on former Cheviot police officers please pm me! Any help or suggestions you could provide would be greatly appreciated and would be a huge help to us.

Thanks for taking the time to at least read my post, hope everyone is enjoying this gorgeous day! :)

Edit: I am only looking for information relating to the Cheviot Police Department and how I might go about looking for former officers. I appreciate the input people have given, but we have all of the basic information we need (birth certificate, census records, marriage license, resting place, family tree, etc.). I am mainly doing this to help my boyfriend learn about who his father was as a person because he won't have the chance to meet him, and I haven't been able to find any of his surviving family for me ask these questions.