I just watched this movie and recall Raymond Leon saying something to the affect that Will's father's crime was giving time away. At another point in the movie, Will tells Sylvia he believes his father was murdered. I pulled these quotes from http://www.moviequotesandmore.com/in-time-movie-quotes-1.html
[talking on the phone]
Raymond Leon: Hello, Will. How much do you want?
Will Salas: A thousand years.
Raymond Leon: You'll never live to spend it.
Will Salas: Then distribute it to the Timelines in Dayton. Do it by sunrise tomorrow and she can go home.
Raymond Leon: Well, I'm afraid for you, Will. You keep talking like him, you're gonna die like him.
Will Salas: Hey, my father died in fight trying to take a man's time.
Raymond Leon: Oh, no. His crime wasn't taking time. He was doing something far more dangerous. Please don't make your father's mistake.
Sylvia Weis: Where's your family?
Will Salas: My mother timed out.
Sylvia Weis: This is her dress?
Will Salas: Yeah.
Sylvia Weis: What about your father?
Will Salas: Died when I was a boy. He was a fighter, strong arm. He wasn't the strongest, but he knew how to win.
Sylvia Weis: How do you win?
Will Salas: I'll show you. [he takes her arm]
Will Salas: What you do is you let them have the upper hand, and then he let his time go all the way down because he knew that when you
were down to your last seconds, and they think it's over, they start
watching your clock and forget to watch their own.
Sylvia Weis: He died in a fight?
Will Salas: I think he was killed for giving away what he won. He wasn't just giving them time, he was giving them hope.