According to today's AJC report, the arrest warrant for Justin Ross Harris alleges that he went to lunch on the day in question. As a result, he would have certainly known his child was in his unattended vehicle while he was at work.
It also shows clear and obvious criminal intent. Criminal intent is the key element that makes the potential charges in this case a Felony rather than a negligent, involuntary manslaughter case.
It was also reported that after work, Harris drove 2 miles with the toddler in the car before he pulled into the Akers Mill Road Shopping Center, which is where he asked bystanders to help him revive the child.
That he drove 2 miles is also extremely suspicious. It makes it look like a pre-meditated attempt to have a story ready.