All these companies have security teams (not network security). Most of them are retired cops, retired detectives, sometimes these companies hire local cops for

All these companies have security teams (not network security). Most of them are retired cops, retired detectives, sometimes these companies hire local cops for big bucks as their VP of security. But they also hire managers of security for local sites. But at the bottom level, they have contracted out to Securitas, Guardsmark, SIS Security, etc. Patrolling, monitoring cameras from a central site, checking locks of all doors, badging, etc--all these have been contracted out. Hospitals are better in this aspect: they hire full timers for the bottom layer, and they also keep contract security firms. Stanford hospital is a good example: they have 70% full time security guards, and 30% is contracted out.