A peace officer, a merchant, or a merchant's employee who has probable cause for believing that goods held for sale by the merchant have been unlawfully taken by a person and that he can recover them by taking the person into custody may, for the purpose of attempting to effect such recovery, take the person into custody and detain him in a reasonable manner for a reasonable length of time. Such taking into custody and detention by a peace officer, merchant, or merchant's employee shall not render such peace officer, merchant, or merchant's employee criminally or civilly liable for slander, libel, false arrest, false imprisonment, or unlawful detention.