Where can I find log files for users logging into network homes?

We're running an open directory master and are using AFP on another server to host our network homes. I was asked to find a log of users logged into their network homes on a specific date and I'm starting to wonder if that's actually a log that exists. I've checked the OD logs and in one of the password logs I can see users have authenticated but it doesn't say specifically to what (so it just lists they logged into something). The AFP logs just show specific files being accessed without usernames. So what am I missing? What log would I check?

Thanks for your help!!