Simplify the following text for a Grade 7 native English-speaking person.
Original: A convict is `` a person found guilty of a crime and sentenced by a court '' or `` a person serving a sentence in prison '' , sometimes referred to in slang as simply a `` con '' .
Simplified: A convict is `` a person found guilty of a crime and sentenced by a court '' or `` a person serving a sentence in prison '' , .