UPPER ST. CLAIR, Pa. (WPXI) — Peters Township resident Khang Nguyen waived his preliminary hearing Wednesday, nearly three months after his infant son died. Nguyen is out on bond after police say he left his 3-month-old son, Kayden, in a hot car for more than six hours in June. It was one of the hottest days of the summer. Nguyen’s defense attorney Bill Difenderfer waived the hearing. Nguyen owns Envy Nail Salon in Upper Saint Clair, and police say he left Kayden in that parking lot when he went into work. The father wasn’t charged until August, when Kayden’s medical examiner report came back. Now, he awaits a trial.