An 11-year-old boy has lost his life days after a fire killed his father's girlfriend.

Charles Runge Jr. died Wednesday afternoon at Lehigh Valley Hospital of smoke inhalation, the Lehigh County coroner's office said.

Runge, of Holland Township, Hunterdon County, New Jersey was inside his home when the fire broke out around 10:00 Sunday night on Hawk Schoolhouse Road.

When fire crews arrived, Charles Runge, 54, was waiting in the front yard suffering from severe burns.  He had been battling the fire's flames trying to save his son and girlfriend, Susan Nash.

Nash died in the fire.

The elder Runge was last listed in critical condition at Lehigh Valley Hospital.

The fire is believed to have started, accidentally, near a wood stove but the investigation is still ongoing.