New details point to a possible premeditated plot in the family murders at Great Wolf Lodge in Pennsylvania, a private investigator says.

Metallica Rose Harrison, 27, is facing two counts of criminal homicide after prosecutors say she stabbed and killed her husband, Charles "Chaz," and the couple's 3-year-old son, Tristan. It happened at the resort in the Poconos region of Pennsylvania.

According to a criminal complaint, knives recovered by investigators on scene did not match knives belonging to the resort.

The document says, "Both knives had teal green handles, which Great Wolf staff confirmed was not a type kept by the lodge."

STEPMOM SAYS GREAT WOLF LODGE MASSACRE SUSPECT DRAINED FAMILY'S 401(K) BEFORE PRICEY WEEKSLONG STAY

The family has confirmed that autopsies for both victims were being conducted. Investigators discovered the father and young son slaughtered in a hotel room at the resort on Monday.