Mary Buehrle is quick to respond when asked why she still searches for her missing sister after more than 40 years.
"I have to keep doing this until I find out something," said Buehrle, who was 8 years old when Pam Hobley disappeared. "I need to know."
Hobley, 15, and a friend, Patty Spencer, 16, were last seen at school in Oscoda, near East Tawas, on Halloween 1969. Peers said the pair planned to skip class then attend the homecoming football game that night.
When neither appeared, relatives called police, who initially thought the teens were runaways, Buehrle said.
For years, both families searched the area, seeking clues at youth hangouts and other locations. But that led nowhere.
Hobley's mother was so dismayed by the disappearance, she moved with her three other daughters several hours south and refused to relax restrictions for their safety, Buehrle said. "Wherever we moved, our grandparents moved with us."
But without her knowledge, Buehrle kept returning to Oscoda and asking authorities about the case.
On the day they were last seen, Hobley, who had dark hair and a scar on her nose, wore a cross, fur coat, plaid skirt, ruffled blouse, white knee socks and chunky shoes. Spencer, who had lighter hair, paired a brown skirt with a similar-colored sweater and shoes, a green and gray jacket and a peace symbol.
The National Center for Missing & Exploited Children has an age-enhanced photo of Hobley on its website. But after so many years, Buehrle cannot fully imagine her sister today.
"It just leaves a hole in your heart," Buehrle said. "You go to bed not knowing where she is, what happened to her. To this day, it still affects me and my sisters."
Several years ago, Buehrle began working with TrackMissing, a group dedicated to helping families and law enforcement locate missing people. Since then, they have scoured sites where Spencer and Hobley were rumored to have visited — including with cadaver dogs.
Buehrle no longer believes her sister is alive, but she desires closure — even if it means a gruesome discovery.
"I would love to know what happened to her, but I just would love to bring her home," she said.
Oscoda Township Police Chief Mark David said the case — the department's oldest involving a missing person — remains active. Prosecutors are reviewing the investigation, and further witness interviews are planned, he said.
Meanwhile, to mark Hobley's 59th birthday Saturday, Buehrle plans to launch balloons in their former hometown.
"Every year I go up and send them to the sky," she said.