Longman Dictionary of Contemporary English
young offender
noun
EXAMPLES FROM CORPUS
▪ Sentence: three years' detention in a young offender institution.
Wikipedia
Young offender
A young offender is a young person who has been convicted or cautioned for a criminal offense. Criminal justice systems often deal with young offenders differently from adult offenders, but different countries apply the term 'young offender' to different age groups depending on the age of criminal responsibility in that country.
Usage examples of "young offender".
As to me, I think my sister must have had some general idea that I was a young offender whom an Accoucheur Policemen had taken up (on my birthday) and delivered over to her, to be dealt with according to the outraged majesty of the law.
The young offender was taken off by his mother, who shook him and said, You have shamed me, you have shamed me.