(CNN) Damon Decree Sr. said while he was shocked to learn his estranged wife and daughter were charged with killing his son and four other family members, he wasn't surprised that something strange was going on in their home.

whose mother and sister are charged in his death. Decree Sr. spoke to CNN affiliate WTVD about the loss of his son, Damon Decree Jr.,whose mother and sister are charged in his death.

Decree Sr. said he believes his estranged wife and daughter were involved in a cult.

"From my niece, apparently they had dissected into some type of cult that they materialized online," he told the news station. "I don't know how, what kind of cult. And they were talking about demons being all around them."

Shana S. Decree, 45, and her 19-year-old daughter Dominique K. Decree are accused in Bucks County of killing their relatives, including three children, at their apartment in Morrisville, Pennsylvania north of Philadelphia.

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