PITTSBURGH (AP) — Authorities say a house fire that killed a married couple was accidental.

The Allegheny County medical examiner’s office said Friday that the victims died of smoke inhalation and carbon monoxide poisoning.

Mt. Lebanon firefighters found 61-year-old Dennis Miller and 56-year-old Susan Miller inside their home after a neighbor reported the fire Thursday morning.

According to the Pittsburgh Post-Gazette, the county fire marshal’s office is still investigating the cause of the blaze.

A joint funeral is planned for Sunday.