A former Yolo County Sheriff's Office lieutenant is one of five people charged with murder following a fireworks warehouse explosion that killed seven workers in the rural Northern California community of Esparto last summer, authorities said. Samuel Machado is accused of illegally having 1 million pounds of fireworks on his property at the time of the blast and using his law enforcement position to shield the illicit operation from scrutiny for years, according to the Yolo County district attorney's office. Machado was placed on administrative leave following the violent July 1 explosion, which was felt by residents up to 20 miles away, destroyed a family farm and sparked a 78-acre grass fire.