Sandra Stiver, 14, and Martha Stiver, 17, were last seen near the El at Frankford and Kensington avenues in Frankford in late spring or early summer 1968.
Last month, officials in Berks County confirmed that DNA tests on two bodies found in 1968 and 1969 were the Stiver girls. Sandy's body was discovered on Aug. 22, 1968, in a patch of poison ivy off Route 82 in Caernarvon Township. She had been shot five times a week earlier.
Marty, who was married to Sandy's brother, Tom Stiver, was discovered atop a flat rock in French Creek State Park. The girls remained unidentified, buried in a potter's field, for decades.
DeMoss, who was 9 years old when her sister disappeared, first made the link between her missing family members and the bodies in Berks while searching through the "Berks County Jane Does" on the Doe Network, a website for missing and unidentified people.
DeMoss said the family would return home to Summit County, Ohio, for a private service.
Martha Stiver's remains will be shipped back to her family in Kansas, Hess said.
Martha's widower, Tom, urged anyone with information about the homicides to call police.
"Somebody out there has to know something," he said. "They gotta come forward."
On Twitter: @JasonNark