Their sudden passing has prompted an outpouring of grief and raised urgent concerns about the dangers of fentanyl-laced drugs. As investigators work to piece together what happened, here’s what we know so far.

The Santa Rosa Police Department is urging parents to talk to their children about the dangers of fentanyl, which is often mixed with other drugs, leading to unintentional overdoses. Even as little as 2 milligrams of fentanyl can be fatal, officials warned.

Two Santa Rosa high school students are dead from a suspected fentanyl overdose. One mom is remembering her 16-year-old daughter, Gia. "That was my blessing and now she is gone forever."