Alicia Witt’s parents passed away on December 20.

Witt grew concerned about her parents after she hadn’t heard from them in a few days.

They were found dead in their home after police conducted a wellness check.

Police reported no trauma on the bodies and fire officials reported no signs of carbon monoxide poisoning.

Officials checked for carbon monoxide after learning that the elderly couple’s furnace had not been working properly.

An autopsy has listed “probable cardiac dysrhythmia” as their cause of death.

The couple is believed to have passed away from exposure to the cold.

It seems that the furnace malfunction was unable to heat the home due to the chilly winter season.

Last month, Witt took to Instagram to say their death “still doesn’t feel real.”