A Jail is a pre-sentence holding facility, where as prison is a facility that holds individuals after they have been sentenced. The main difference between the two is that false arrest requires an arrest, but, false imprisonment only requires unlawful detention.The only distinction lies in the manner in which they arise. False arrest is merely one means of committing a false imprisonment. Jail is usually a local faciility for local short timers less than 12 months, usually. Our jails provide a safe environment for inmates, staff and visitors. If you do not follow the jail rules, you can expect consequences for your actions. The plaintiff's claim in a warrantless false arrest lawsuit arose from a sheriff s deputy s visit to her house to check on the welfare of her daughter. The primary aim of imprisonment is protecting the immediate society against criminal offenses while depriving the defendant of their freedom. "Wrongful imprisonment" redirects here.