Troy tells both the audience and Lyons and Bono about his past in Act I scene 4, which includes the story of how he came to be put in prison due to the accidental murder of somebody he was trying to rob when he was going through a very difficult stage of his life. Note how he tells his history in his own words:
Went to rob this fellow... pulled out my knife... and he pulled out a gun. Shot me in the chest. I felt just like somebody had taken a hot branding iron and laid it on me. When he shot me I jumped at him with my knife. They told me I killed him and they put me in the penitentiary and locked me up for fifteen years. That's where I met Bono.
The murder Troy committed was therefore "accidental" because in a sense he was trying to protect himself from being shot again, and he was already wounded. His time in prison is significant as it led to Troy being introduced to baseball and also resulted in his friendship with Bono, which is very significant for Troy and for the play. Troy's account of his past suggests that he turned to crime out of poverty, as he suggests he turned to crime in order to be able to feed his wife and son. Troy's crime therefore explores the position of blacks in American society at the time, and how their limited options produced massive dilemmas as to how they were going to provide for themselves and their families.