Tony Bortner was last seen Oct. 17 and his red SUV was found two days later near the Lock 12 Historic Area in Lower Chanceford Township.

Volunteers have been scouring a 4-square-mile area near the Susquehanna River for more than a week, including Saturday. Middle Creek Search and Rescue in Ephrata and Pennsylvania State Police are also searching for Bortner using drones and dogs.

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Middle Creek Search members are trained in grid search techniques, maps and compasses, crime scene awareness and interview methods, according to the organization’s website.