While she was in the system, Parker never fit in. Moving from one home to another constantly didn't help. Most families she was with had plenty of other adopted kids there, who already knew each other.
One boy was nice to her, his name was Michael. They talked and grew very close, even though he was 3 years younger than her. She grew protective of him, and he always made the other kids include her in their games. Mostly they played happy family (which was too boring for Parker) but sometimes they played more fun games.
They were playing cops and robbers this time. Most of the kids wanted to be cops and so they made her be a robber. She took her role too seriously, and stole everything from their pockets.
Then, the race ensued on bikes. Michael was a cop in pursuit and, despite the age difference, was gaining on her. She swerved into the street wondering if he had the guts to follow. He did. Neither of them heard the car speeding down the road, and before she realized, it was too late.
She didn't grasp what had happened until the next day, when she had no one to talk to. The kids resumed playing games without her. The foster parents seemed upset and took out their anger on her because she was the only kid that stayed inside all day.
Parker had the scars to prove it. That was what led her to act out and when she realized that the sneaky ones didn't get punished, she got better.
She believed because of the incident, being good is what gets you caught.
Parker blamed Michael's death on herself- always has, always will.