State Rep. John Mizuno said the U.S. government has been “silent” on the unexplained May 20 death of a 16-month-old boy under the care of his Marine Corps father, and he wants a formal military investigation into the case.

Mizuno was flanked by about 30 people outside the state capitol Thursday afternoon, including the boy’s mother, Jerlee Bahm, before the group started a silent march to remember her youngest son, Ernest.

“It’s a possible wrongful death case,” Mizuno said. “We don’t have enough information. We just ask that the military conduct a formal investigation.”