Question: After being found not guilty, why would Joe whisper to Randall that he would kill more kids?
Answer: Joe was taunting him because Randall was a do-gooder who thought that he could change the world for the better but just made things worse.
Answer: Because the DVD wasn't actual footage of the crime. It was a CGI re-enactment. However, 2 versions were made. The one meant for trial and one where Dalton's face was photoshopped onto the CGI killer. A.D.A. Paxton put the wrong DVD in and the jury saw a Dalton as the killer, which was declared prosecutorial misconduct and the video tainted the jury.
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