'48 Hours' Preview: Mary Day's 1981 Disappearance Investigated After Case 'Gets Weirder And Weirder'

On Saturday night, "48 Hours" will investigate the 1981 disappearance of Mary Day as CBS correspondent Maureen Maher takes a closer look at the circumstances involved in the case and the details that have been uncovered throughout the investigation.

In 1981, the 13-year-old vanished without a trace. According to her sister Sherri Calgaro, she "just knew" something had been wrong in their house leading up to her disappearance. One day she was in California and the next she was "gone."

Mary's mysterious whereabouts prompted her sister to begin asking questions regarding where she could be. One night, in particular, she asked what had happened to her and was told that they were "not allowed to talk about Mary."

According to someone who worked on the case, it was difficult to deal with for a variety of reasons, including the fact that no one outside of the child's family seemingly knew she was missing. In addition, it appeared as though other family members, aside from Sherri, were not concerned with her whereabouts.

As seen in the preview below, Mary's mother, Charlotte Houle, later told investigators that her daughter had developed a habit of running away over the years as a way to explain where Mary could have been. However, Sherri eventually started to believe that she had been murdered after spending some time investigating and hearing her mother say that there were many places in California that you could hide a body.

After some time, police were eventually led to a home where cadaver dogs indicated that human remains had been buried on the property. While the search at the site was unsuccessful when it came to locating Mary, a young girl's shoe was found on the property.

Following the discovery, the case went cold, until 22 years later when police began focusing on her stepfather, William, as a suspect. He would later reveal to investigators that he didn't kill Mary, but had been told by his wife that he had been "possessed" on the night of her disappearance and that he had had a "demon inside of him."

Later, the case would take yet another turn when police developed new suspicion that they may, in fact, have found Mary Day herself.

During Saturday's new episode, the case that "gets weirder and weirder" will be fully explored on the CBS crime show.

The new episode of "48 Hours," called "What Ever Happened to Mary Day?", will air Saturday at 10 p.m. EDT on CBS.