Court Proceedings Advance Against Four Defendants in Child’s Death
The investigation into the fatal hyperbaric chamber explosion that killed 5-year-old Thomas Cooper in Troy, Michigan, on January 31, 2025, is moving forward in court. The incident occurred at the Oxford Center, a facility offering hyperbaric oxygen therapy for conditions such as autism and ADHD.
In March, Michigan Attorney General Dana Nessel announced charges against four individuals. Tamela Peterson, 58, CEO of the Oxford Center; Jeffrey Mosteller, 64, Safety Manager; and Gary Marken, 65, primary management assistant, were each charged with one count of Second-Degree Murder, a potential life offense, or alternatively, one count of Involuntary Manslaughter, punishable by up to 15 years in prison. Aleta Moffitt, 60, the technician operating the chamber that day, faces one count of Involuntary Manslaughter and one count of Intentionally Placing False Information on a Medical Record, a four-year felony.
According to the Attorney General’s office, the hyperbaric chamber ignited from the inside and burst into flames while Cooper was receiving treatment. Officials stated that both the National Fire Protection Association (NFPA) and Sechrist, the chamber manufacturer, publish strict safety protocols, which the defendants allegedly disregarded. “This tragedy could have been prevented if proper safety protocols were followed,” Attorney General Nessel said. “Instead, deliberate negligence and a blatant disregard for safety cost a child his life.”
Court Proceedings and Facility Inspections
On April 30, all four defendants appeared for a probable cause conference. Attorneys agreed that an inspection of the Troy facility was necessary before preliminary hearings could continue. A temporary restraining order remained in place to preserve evidence. Marken’s bond conditions, including restrictions on travel and church attendance, were reviewed by Judge Maureen McGinnis.
By May 28, additional conferences addressed delays and evidence handling. The defense raised concerns over access to discovery materials and whether privileged communications were affected. The court scheduled further hearings to finalize evidence protocols.
Recent Motions and Statements
On July 14, Peterson returned to court for a motion hearing regarding law enforcement’s handling of her electronic devices. The motion was denied after Assistant Attorney General Chris Kessel argued there was no evidence of improper access. However, the court approved Peterson’s request to visit the Oxford Center’s Brighton location under strict conditions to facilitate a property sale.
Throughout the investigation, Troy Police Chief Josh Jones stated, “These arrests reflect the dedication and commitment of our investigators.” The criminal probe was led by the Troy Police Department in coordination with the Attorney General’s office.
Next Steps
The preliminary examinations are scheduled for September 15 and 16, 2025. The court will determine whether the charges—including second-degree murder, involuntary manslaughter, and falsification of medical records—will proceed to trial. As proceedings advance, questions remain about whether industry fire safety standards were followed and whether regulatory gaps contributed to the incident.
Sources:
Michigan Department of Attorney General – Press Release
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