During the Middle Ages, crimes were very common. This was caused because of impunity among other reasons which caused burglars and thieves exert more frequently their activities. Of course, education also played a primary role in this as most burglars had no education at all and thus; instead of working they would simply resort to steal.
Your are sentence to death
Billy was almost at his house but the sherrif was right behind him!
Billy got home in time to feed his family.
Punishment for thieves varied greatly. Medieval torture was used mostly even if the thief only stole bread to feed himself. Of course death to thieves very rarely happened and they were just publicly tortured.
He spent the night in a jail cell. Some kings who were especially obsessed with their kingdom's honesty, attempted to capture every criminal. If a criminal got away with a crime, a some kings went to the nearest village to kill people out of spite.
Kidnapping was very frequent during the Dark Ages. This was mostly done by foreign invaders who needed kids to work their own lands. Landlords who lacked enough workers, frequently resorted to kidnapping kids in order to populate their own villages. Punishment for these crimes were of a very high magnitude and if the kid was part of the royalty, the offender would be heavily tortured and executed in a public plaza.