sentences:  If the shopkeeper exceeds the bounds of this privilege and makes an arrest, the lawfulness of his action will be determined by the jurisdiction's rules governing arrest by a private citizen.The shopkeeper's privilege is for the purpose of investigation only; if, after reasonable detention and investigation, the shopkeeper mistakenly concludes that the suspect is guilty and has him arrested, the shopkeeper may become liable for these acts just as he would have been had he committed them without undertaking a prior detention and investigation.Statutes in many states have modified and in some cases broadened the common law privilege, for example, by expressly permitting detention of the suspect until the police arrive.