David Zandstra, of Marietta, Georgia, will return to the Keystone State on Thursday, Sept. 28.
Prosecutors have said Zandstra admitted to killing 8-year-old Gretchen Harrington of Marple on her way to summer Bible camp on Aug. 15, 1975.
She and other campers would meet at Zandstra's parish, Trinity Church in Broomall, before heading to Reformed Presbyterian Church in Chester County, where her father was the pastor, authorities said.
Police said Zandstra was ordinarily one of the adults responsible for taking the children up to Reformed Church.
On the day of her disappearance, Harrington never arrived at Reformed with the other campers. Her father "became concerned" and reported her missing to Marple Township Police later that morning, according to the DA.
Her skeletal remains were found months later in Ridley Creek State Park, Edgemont Township on Oct. 14, 1975. The coroner determined she died of blunt impacts to the head and called her death a homicide.
During the initial investigation, a witness told police they saw 8-year-old Gretchen "speaking with the driver of either a green station wagon or a two-tone Cadillac" on the morning of Aug. 15.
Zandstra, who drove a green AMC Rambler, was interviewed around that time but denied seeing her on the morning of her disappearance, authorities said.
The trail went cold for nearly 48 years until January 2023, when detectives spoke with an old friend of Zandstra's daughter.
The friend told investigators that she once woke up during a sleepover at Zandstra's house to find the pastor "groping her groin area," said the DA.
When the witness told Zandstra's daughter about it, she reportedly replied that her father "did that sometimes."
The witness also showed detectives a page from her 1975 diary, where she wrote about a child in her class nearly being kidnapped twice. The witness said at the time that she believed Zandstra was the attempted abductor, according to investigators.
Detectives then traveled to Marietta, Georgia to interview Zandstra on Monday, July 17. He initially denied any knowledge of the 8-year-old's murder but police say he changed his story "after being confronted with the evidence (...) of his sexual misconduct."
"He admitted to offering Gretchen a ride and taking her to a nearby wooded area," the DA's Office said. "He stated that he had parked the car and asked the victim to remove her clothing."
"When she refused, he struck her in the head with a fist," prosecutors have said. "The victim was bleeding, and he believed her to be dead. He attempted to cover up her body and left the area."
Zandstra was arrested and taken to a Cobb County, Georgia jail while prosecutors sought his extradition. He is charged with criminal homicide, kidnapping a minor, and related counts.
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