Squid Security/Custom Log File Reader Required

I have some proxies running off linux vps. They are set up with squid. I let some people use them for anonymity but now I am getting worried they're using them for not so good purposes. I want to know exactly what my users are doing, from start to finish, so i dont get any drama from sites like Craigslist, etc. I'm looking for someone who KNOWS squid 3.0 like the back of their hand. Someone hopefully with beefy creds (nice but not 100% necessary) who can build me or guide me to software (custom or not, whatever can do this) that can extract the entire browsing history including all activities (even chats) from the Squid log files.