Michigan Attorney General Dana Nessel will announce charges against the four people who were arrested in the case that led to the death of a 5-year-old boy who was

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.

Thomas Cooper was pronounced dead at the scene on Jan. 31 at the Oxford Center in Troy. His mother suffered burn wounds as she tried to save her boy.

Allegedly, neither a medical doctor nor a safety supervisor was at the medical facility when the chamber exploded.

The Michigan attorney general has accused the owner of a medical center and three of its employees of ignoring safety standards to make a profit.

Michigan Attorney General Dana Nessel has charged four people in connection with the death of a 5-year-old boy who was killed in a hyperbaric chamber explosion.

Troy police say Tamela Peterson ran away when asked for her cellphone after Thomas Cooper died in a hyperbaric chamber fire at the Oxford Center.