What police officers are doing is an ancient ritual

"Oh great computer, please telleth us if we can busteth this peon"

The media will have you believe that the police have a database of bad guys. But, what they really have is a database of :

• people who got ratted out (under torture)
• people who failed to pay a fee (dmv)
• people who have been arrested before

No one in this database is guaranteed to be a bad guy. In fact most aren't.

Soooo, what a police officer does is bully you into confessing anything, and then take you into their torture chambers and bully you into confessing more.