Without contacting an ISP
I don't think this is possible. The IP address might not be a static IP meaning the the person on an IP right now may not be the same as the person that was on that IP 10 minutes ago. Some ISPs assign the IP when a user connects to their system. You would need the ISP to tell you who was using the IP at the time of whatever offense you are looking into. If they were using a proxy, Tor, or VPN you may never be able to find out who it is.