Okay, this is bad. We knew that there was some type of dispute with his ex-girlfriend but the details in Miami's student newspaper make this look even worse.
According to the Miami Student report, Harwell went into his ex's storage shed looking for some items he claimed belonged to him, then sent her a text message about it. He then went into her car and took a cap and gown (I'm assuming the graduating kind) that she bought for him but wasn't going to give them to him until he paid her for them. Then Harwell kicked in the front door of her apartment, causing the ex-girlfriend and her roommate to lock themselves in their bedroom out of fear, given that she had reportedly been physically harmed by Harwell in the past.
All of this sounds awful, especially that last part. Based on what he was arrested for (unauthorized use of a vehicle, vehicle trespass, criminal damaging, theft) he could have been charged with a lot worse.