The Lead Masks Case (Portuguese: O Caso das Máscaras de Chumbo) was a series of events which led to the death of two Brazilian electronic technicians: Manoel Pereira da Cruz and Miguel José Viana. Their bodies were discovered on August 20, 1966.
Miguel José Viana and Manoel Pereira da Cruz
On the afternoon of August 20, 1966, a young man was flying a kite on the Morro do Vintém (Vintém Hill) in Niterói, Rio de Janeiro, Brazil,
when he came upon the bodies of two deceased males and reported them to
the authorities. The Morro do Vintém had difficult terrain, and the
police were unable to reach the bodies until the next day. When a small
team of police and firefighters arrived on scene, they noted the bodies'
odd conditions: The two males were lying next to each other, slightly
covered by grass. Each wore a formal suit, a lead eye mask, and a
waterproof coat.
Murders in Southern California (Goleta, Ventura, Dana Point, and Irvine,
California) were not initially thought to be connected. One Sacramento
detective strongly believed the East Area Rapist was responsible for the
Goleta attacks, but at first the Santa Barbara County Sheriff's
Department attributed them to a local career criminal who had himself
subsequently been murdered. Investigating the crimes that did not occur
in Goleta caused local police to follow false leads related to men who
had been close to the female victims. One suspect, later acknowledged to
be innocent, was charged with two murders. Linking all of the cases
together was achieved almost entirely by DNA testing, which was not done
until many years later.

