Best Answer - Chosen by Voters
They dig really deep. When you fill out a background form, most places will ask for the names, phone numbers, and addresses of past and present bosses, landlords, co-workers, roommates, neighbors, sometimes even coaches or teachers, along with friends and family. Of course every department is different and there are places that don't go into as much detail. They will check your credit, driving record, criminal record, debts, and yes, Myspace and Facebook. The reason for all of this is to check your quality of character, along with the obvious things like criminal history, etc. If on your Myspace, you list "drinking, partying, and getting into trouble" as your interests, you can be pretty sure you won't get hired. They also look at your top friends and who's written on your wall or left you comments. If those people look like shady characters, you're in trouble too. If your buddies have pictures of them smoking pot or drinking underage, it looks bad on you, because in their eyes, you should care enough about the law to not even hang out with people who do. And don't even try to lie and say you don't have those online accounts, or put them to private for a few weeks. My fiance had buddies who were made to log into their accounts at their interviews. If you try to lie, they will find out. Don't try to outsmart cops, it's just stupid. Background checks are serious investigations into your whole life. They know everybody's done stupid things in their pasts, they're not asking that you've been perfect your whole life (and don't try to lie about that either, they'll catch you on your polygraph), but there's a limit. Even if you used to smoke pot and quit, but you still have pictures or references to it online, you're probably in trouble too.
Source(s):
Fiance's a cop.