Former pastor charged with killing 8-year-old girl who was walking to Bible camp nearly 50 years ago

David Zandstra has been charged with the kidnapping and murder of Gretchen Harrington, whose remains were found in a state park two months after she disappeared

A retired pastor has been arrested and charged with the kidnapping and murder of an 8-year-old girl on her way to a summer Bible camp nearly 50 years ago.

David Zandstra, 83 — who resides in Marietta, Georgia — confessed to the August 1975 murder of Gretchen Harrington in Broomall, Pennsylvania, after investigators interviewed him, according to a statement by the Delaware County District Attorney’s Office.

“We’re going to try him, we’re going to convict him and he’s going to die in jail,” Delaware County district attorney Jack Stollsteimer said at a news conference on Monday. “And then he’s going to have to find out what the God he professes to believe in holds for those who are this evil to our children.”

At the time of Harrington's murder, the Bible camp was held in two churches in Marple Township: the Reformed Presbyterian Church, where her father served as a pastor; and the Trinity Church Chapel Christian Reform Church, where Zandstra was pastor, according to the statement.

Harrington’s schedule for the day she vanished included a visit to Trinity and then a stop at her father's Reformed church with the rest of the campers later on, the release added.

Tragically, she did not arrive with the group at the second location and when her dad called Zandstra — who was one of the people in charge of transporting the children — he said that the young girl had not arrived at his own church earlier in the day, according to the district attorney's office.

On Oct. 14, 1975, Harrington’s skeletal remains were discovered at a state park in Edgemont Township. The coroner classified her death as a homicide, determining she died of blunt impacts to the head, according to the release.

"This man is evil," Stollsteimer said at the news conference. "He killed this poor 8-year-old girl he knew and who trusted him. And, then, he acted as if he was a family friend, not only during her burial and the period after that, but for years.

Zandstra’s neighbor, Karen Alsdorf, painted a different picture of the former pastor, according to WSB-TV.

“They’ve been wonderful people. They’ve always checked on us,” she told the outlet. I just can't believe it.

In January, a friend of Zandstra’s daughter told investigators that she often stayed over at the family's house and once woke to find Zandstra groping her, according to the district attorney’s release. At the time she was just 10 years old and also recalled that a child in her class was almost kidnapped twice around the same time. In her diary, she wrote she suspected Zandstra may have been involved, the release added.

The Christian Reformed Church website says Zandstra was ordained as a minister on Sept. 20, 1965 and is now retired. He served at churches in New Jersey, California and Texas between 1965 and 2005, as well as the Trinity Chapel Christian Reformed Church in Broomall.

“We are additionally grieved to hear that a C.R.C. pastor has been arrested for her murder,” the church said in a statement on Monday, The New York Times reported. “We recognize that we live in a broken and sinful world where violence can happen anywhere by anyone — even within our churches and by leaders we hold to the highest standards.”

“It’s difficult to express the emotions that we are feeling as we take one step closer to justice,” Harrington's family said in a statement on Monday, per the outlet. “The abduction and murder of Gretchen has forever altered our family and we miss her every single day,” they said, adding that they were “extremely hopeful that the person who is responsible for the heinous crime that was committed against our Gretchen will be held accountable.”

The Delaware County District Attorney's Office did not immediately respond to PEOPLE's request for comment.