What is the criminal background of boy in twelve angry men?

The play "Twelve Angry Men" does not explicitly state the criminal background of the boy on trial. The focus of the play is on the jury's deliberation process and how they grapple with the evidence and their own biases.

However, we learn the following about the boy's situation:

* He is accused of murdering his father. This is the central crime being debated.

* He comes from a poor, disadvantaged background. This is mentioned by Juror 8 and is a factor in some jurors' initial biases against him.

* He has a history of violent behavior. This is suggested by the fact that he was in a reformatory school, and his actions in the play are interpreted by some as aggressive.

* He is described as a "wild" and "delinquent" child. This again points to his troubled background.

The lack of specific details about his criminal history allows the play to explore broader themes of prejudice, justice, and the responsibility of the jury. The audience is left to speculate on the boy's past and how it might influence their interpretation of the evidence.