This Book by a Marple Newtown High School Grad Details an Unsolved Philly Murder

Featured Courtesy Tessa Marie Images.

Author Joanna Falcone tells the tragic story of Gretchen Harrington, a memory from her childhood, in her new book.

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On August 15, 1975, 8-year-old Gretchen Harrington set out for Bible school three-quarters of a mile from her home in Marple Township. She never arrived. Her body was discovered two weeks later. Joanna Falcone Sullivan and Mike Mathis were both 9 years old at the time and living in the township. Sullivan, a graduate of the University of Maryland as well as local Marple Newtown High School, and Mathis, a Villanova grad, detail the horrendous crime’s impact on their hometown in the recent book Marple’s Gretchen Harrington Tragedy: Kidnapping, Murder and Innocence Lost in Suburban Philadelphia (The History Press, 112 pages).

MLT: What’s your connection to the case?

JFS: My family had moved to Marple from South Philly—the picturesque, safe suburbs, so we thought. I was at the swim club the day Gretchen disappeared. I’ll never forget it—it affected all of us. But it didn’t even make the news. The prime suspect died in jail for crimes against other children, but he wasn’t convicted for this one. The ’70s was an era of serial killers—a crop of them. A lot of women and girls disappeared.

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MLT: Why the book?

JFS: I always wanted to write this story. It started as fiction, until I realized that people were still talking about it. It was something that shook the kids and parents. There were long Facebook strings of “I remember it like yesterday…” and comments from people in the search party, like Mike’s dad. I didn’t have the time for a book until the pandemic hit. But a Facebook message led to a call, which led to the decision to do it.

Joanna Falcone Sullivan, journalist and author
Joanna Falcone Sullivan, journalist and author. Courtesy Tessa Marie Images.

MLT: What was the collaboration like between you and Mike?

JFS: We had a phone call each Tuesday to coordinate remotely. The Marple police were great. We looked through the evidence box three times and talked to as many of the main people from the Bible school and neighborhood as we could. We’re hoping the book will help solve the case.

MLT: Any new revelations since the book was published?

JFS: I got an email from Gretchen’s sister. She thanked me for making her parents look human. She opened up her home and her heart. That meant a lot.

Update: Nearly 48 years to the day later, Charges were brought to former Delco pastor, David Zandstra, 83, for the murder of Gretchen Harrington in 1975. Having reportedly admitted to the crime, he is currently being held in prison in Cobb County, GA. He’s planned to be tried in Delaware County with criminal homicide, first-degree murder, second-degree murder, third-degree murder, kidnapping of a minor and possession of an instrument of crime.

Related: Why True Crime Has a Hold on Many Main Line-Area Residents

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