By WCCO-TV Staff

MINNEAPOLIS (WCCO) — Investigators say the cause of a deadly July house explosion in central Minnesota is undetermined.

Earlier this month, Princeton Fire and Rescue and the Princeton Police Department closed their investigation into the July 22 explosion, which left Eugene Meyer dead. The 85-year-old’s son and grandson suffered severe burns in the blast but survived.

The investigation could not determine an exact cause of the explosion.

An earlier investigation with the Minnesota State Fire Marshal’s Office and the Minnesota Office of Pipeline Safety found that a natural gas valve that supplied a clothes drier in the home was found in the “open” position. However, it was undetermined if the valve was open prior to the explosion.

Investigators say the ignition source of the blast was in the kitchen area of a gas range on the home’s main floor. Yet, it was never determined what exactly sparked the blast.