BOGOTA, Colombia (AP) — The weary Indigenous men gathered at their base camp, nestled among towering trees and dense vegetation that form a disorienting sea of green. They sensed that their ancestral land — Selva Madre, or Mother Jungle — was unwilling to let them find the four children who'd been missing since their charter plane crashed weeks earlier in a remote area in southern Colombia.

Indigenous volunteers and military crews had found signs of hope: a baby bottle, half-eaten fruit, dirty diapers strewn across a wide swatch of rainforest. The men were convinced the children had survived....