In Girl, Stolen, Two characters by the name of Jimbo and TJ get into an argument over whether or not to shoot Griffin. In this conversation, they reveal that Roy killed Griffin's mother. In the end, TJ has enough of Jimbo's insults and shoots him.
This quote shows that TJ is a terrible person, and does not mind killing people. Then again, the man he shot was Jimbo, who provoked TJ into getting in trouble multiple times.