Guard Jesus Antunes Moreira reported an encounter at the Marimbonda hydroelectric plant near Fronteira on 6 December 1978. At about 8:30–8:45 p.m., during rain, he saw a luminous object approach across the water. Initially mistaken for a company helicopter, it was allegedly silent. As it neared his guardhouse its brightness diminished, revealing a round, conical vehicle with a platform and a door containing a small upper window.
Three tall, human-looking visitors reportedly emerged wearing metallic-blue overalls and pink gloves, with smooth black hair. They spoke an unfamiliar language and discouraged Moreira from telephoning for assistance. He said a revolver failed when he tried to fire a warning. After one visitor raised a shoebox-sized device, he understood speech in Portuguese: they claimed to be conducting research. One version includes stone collection before the visitors returned aboard and departed rapidly.
Walter Bühler’s published account was preliminary. Later CIPEX material differs in dimensions and describes one woman and two men. The imported HOX flag and subsequent suspicion of invention do not supply a demonstrated confession. Marimbonda is the dam on the São Paulo–Minas Gerais border, not the imported Maribondo/Mato Grosso location. The composite plate preserves the visitors’ reported human appearance and distinctive clothing.
Retain preliminary Bühler provenance, later CIPEX differences, correct São Paulo–Minas Gerais location and unresolved importedHOXflag. Narrator calling this authenticated does not independently establish the event.
