Law Enforcement Social Media policies?

[Matt]

I`m majoring in Criminal Justice and when I turn 20 I plan on taking the State Trooper test. I`m already aware that when someone enters into the field there are strict social media restrictions that have to be followed. I don`t think I`ll have a problem with this seeing as I don`t have Twitter and if I post something on Facebook I make sure it`s not something stupid. What interests me though is a fact my dad heard from a trooper, and he told him that once you apply, they question everyone on your friends list. I`m not worried about that in the least, but it leaves me wondering exactly how they go about doing that. Does that happen over a period of time and/or what questions do they ask them? If anyone has good info or a site they can direct me to that be great. Thanks.