Arresting Authority

• Private security guards have no more power by law than an average citizen, but typically foster compliance because they or the offender doesn't understand the limits of the guard's authority. State laws vary regarding citizen's arrest, but typically permit a merchant or security guard to "detain" an offender, such as a shoplifter, long enough to request and verify identification, and inquire about the alleged crime, without handing him over to the police, according to Robert J. Fischer, Edward Halibozek and Gion Green in "Introduction to Security."
  
  

Search and Seizure

• The Fourth Amendment grants protection from unlawful search and seizure, but scant legislation regulates searches by citizens. Security guards have no special searching authority, but management may bar entry to anyone refusing a search of her belongings. Police officers, once called to the scene, can obtain a warrant.
  
  

Liability

• Liability laws apply to everyone, with agencies, corporations and individual employees subject to charges and lawsuits. Security officers risk criminal or civil liability if accused of committing a crime on duty, such as false arrest, assault or unlawful use of a weapon. Police officers have further oversight through their department's regulations and operating procedures.