Three people have been charged with second-degree murder after a 5-year-old boy was killed when a hyperbaric chamber exploded at a medical facility in Michigan earlier this year, officials announced Tuesday.

Two other people were arrested Monday and also are expected to be arraigned in the child's death, police said.

Four people have been charged in the death of a 5-year-old boy who was killed inside a pressurized oxygen chamber that exploded at a suburban Detroit medical facility.