Several weeks after his devastating passing on April 2, Logan Williams’ cause of death was revealed by his mother. The Flash actor, who died tragically at 16-years-old, passed away of a fentanyl overdose, according to preliminary toxicology, Marlyse Williams told The New York Post. “His death is not going to be in vain,” she said, while noting that Logan battled addiction for three years. “He’s going to help a lot of people down the road.”