Store detectives may be self-employed on a contract basis but most are employees of the retailer, of a security firm with an outsourcing arrangement with the retailer, or of an agency with a similar agreement.
The job involves patrolling stores in the role of an ordinary shopper, watching for shoplifters. The detective follows any shopper behaving suspiciously, and keeps records of such observations. The key difference between a store detective and a security guard is that the former's role is covert. Store detectives can detain and arrest individuals they actually see committing an indictable offence such as stealing, but so can any ordinary citizen. Otherwise, store detectives have no legal right to detain people, search them or ask a person to accompany him/her to a store office.
Most stores require their detectives to have stable work histories and no criminal record. Common backgrounds include the armed services, rescue services, and security. In the UK, distance learning courses in store detection are offered by The Security Industry Training Organisation.