Police in Delaware County and elsewhere are reexamining cases from the 1970s in light of last week’s arrest of David Zandstra in the abduction and murder of Gretchen Harrington in 1975, writes William Bender for The Philadelphia Inquirer.

David Zandstra, a retired reverend who served at Trinity Chapel Christian Reformed Church in Marple back in 1975, confessed to Gretchen’s murder after new evidence and a key witness were presented.

The witness talked with state police in January 2023 after a book on the murder was published by Joanna Sullivan and Mike Mathis.

She told police that at age 10 she was friends with Zandsra’s daughter and frequently slept at his home.

During two sleepovers she woke up to Zandstra touching her. In a September 1975 diary entry, she wrote that Zandstra might have been involved in the attempted kidnapping of a girl in her class and Gretchen’s disappearance. 

Sullivan said she has been receiving phone calls and Facebook messages from Marple residents with information about other abuse cases.

“I don’t think it was an isolated case,” Sullivan said.

Delaware County District Attorney Jack Stollsteimer said Zandstra’s arrest was a “great relief” to police in Delaware County.

Read more about the latest developments in David Zandstra’s arrest in The Philadelphia Inquirer.

Two local book authors talk about how they helped in the 1975 cold case investigation.