WORCESTER, Mass. (AP) — The parents of actor Alicia Witt who were found dead in their Massachusetts home in December died of exposure to the cold, according to the state medical examiner's office.

The cause of death for Robert Witt, 87, and Diane Witt, 75, was “probable cardiac dysrhythmia” due to the cold, according to death certificates issued Wednesday, The Telegram & Gazette reported.

The Witts were found in their rundown Worcester home on Dec. 20 by police after Witt asked a relative to check on them because she hadn't heard from them in several days.

Police said at the time the home's heating system was not working.

Witt said in a social media post last month that she had repeatedly offered her parents help, but was always turned down. She called her parents “fiercely stubborn" and said she had no idea they were without heat.

“Every time I offered to have something repaired for them, they refused to allow workers into their house," she wrote. “I begged, cried, tried to reason with them, tried to convince them to let me help them move — but every time, they became furious with me, telling me I had no right to tell them how to live their lives and that they had it all under control.”

Witt, 46, made her acting debut at age 7 in 1984's “Dune” and has also appeared in “Orange Is the New Black,” “Twin Peaks” and “The Walking Dead.” She is also a classically trained pianist and recording artist.