Inside Mary Louise Day’s Missing Persons Case: Teen Disappears in 1981, Allegedly Resurfaces 22 Years Later

Their childhoods were unstable. As their mother, Charlotte, navigated multiple marriages, affairs and a suicide attempt, siblings Mary Louise Day, Kathy Pires and Sherrie Calgaro spent time in foster care. Sherrie, the youngest, was ultimately adopted by another family while her half-sisters returned to their mom, who raised them with third husband William Houle, a soldier. But in the summer of 1981, 13-year-old Mary vanished from their Seaside, California, home without a trace.

Kathy and Sherrie were told their sister had run away; the family didn’t speak about her. It never made sense to Sherrie, who as an adult contacted police — and discovered her mom and stepdad had never reported Mary missing.

For years, Sherrie had “a hole in my heart wondering what happened to her,” she said in The Girl Who Died Twice, a new installment of Investigation Discovery’s The Curious Case of… series. “I fear my birth mother and her third husband, William, murdered my sister.”

Cops had the same suspicions as circumstantial evidence mounted — until a woman claiming to be Mary suddenly reappeared 700 miles away. As former Seaside Police Chief Steve Cercone told 48 Hours in 2021, “This case just gets weirder and weirder.”

Detectives opened a missing persons investigation in 2002. They’d learned that on the last night Mary was seen, she and her stepdad got into an argument that turned physical. William denied murdering Mary, though confessed he’d been so angry, it was as if he had “a demon” in him — and he admitted “the demon could have killed Mary,” former Seaside Detective Joe Bertaina recalled.

The case became a suspected homicide investigation. Four cadaver dogs separately alerted police to the same area in the backyard of the Houles’ former home. A dig uncovered a child’s shoe, a teddy bear and a belt buckle, but no body.

Then came a shocking twist: In 2003, cops conducting a routine traffic stop in Phoenix, Arizona, encountered a woman who was Mary.

“She knew the basics of [Mary’s] life and her family, but not a lot,” Detective Bertaina said.

Fearing “Phoenix Mary” was an imposter, a DNA test was ordered. It confirmed Charlotte was the woman’s mother. Some remained unconvinced. Mark Clark, another detective who worked on the case, theorized Charlotte had another child who was pretending to be Mary.

“Phoenix Mary,” Detective Clark told 48 Hours in 2021, “was somehow sought out by Charlotte and William to pose as Mary Day [so they could] avoid prosecution.”

(The couple denied any wrongdoing and were never charged.)

Until her death in 2017, “Phoenix Mary” insisted she was the real Mary.