A witness must have called 911 or officers were in the area??
clipped:
Witnesses told police they heard "squealing tires, and the vehicle came to a stop." Harris got out of the car yelling, "Oh, my God, what have I done?"
Harris then stood there with a blank look on his face. When a witness told Harris his son needed CPR, Harris went to the other side of his vehicle and made a phone call, apparently to tell someone his son was dead, a witness told police.
Harris never called 911, and when an officer told him to get off his phone, he refused and even said, "*advertiser censored** you" before an officer took his phone and handcuffed him.
http://www.cnn.com/2014/07/07/justice/georgia-hot-car-toddler-death/