classroom theatre room. surrounded by memories of their son. he loved school, loved sports, starred in the musical. he was such a stellar young man. he always wanted to help other people. reporter: zach s sudden death initially a mystery to investigators. but the coroner had two theories, either an undetected medical issue or fentanyl. and that further spiralled us into into confusion. yeah, debilitating confusion. why would you say that word. we had no red flags of zach having struggles with any drug use or addiction or depression. reporter: nine out of every ten overdose deaths in teenagers involves opioids. and most common, fentanyl. fentanyl is so potent that
classroom, surrounded by memories of their son. he loved school. he loved sports. he starred in the musical. zak was such a stellar young man. he always wanted to help other people. zach s sudden death unnaturally mistreat investigators. but the plaster county corner near sacramento had two theories on the davis debt, either an undetected medical issue or fentanyl. that further spiraled us into confusion. debilitating confusion, why would you say that word? we had no red flags of zach having struggles with any kind of addiction or depression. nine out of every ten overdose deaths in teenagers involves opioids. most commonly, it involves fentanyl. doctor scott haviland s head of adolescents and young adult medicine at boston s mask general for children s hospital.