On August 20, 1966, a boy flying a kite on Morro do Vintém (Vintém Hill) near Rio de Janeiro stumbled upon two bodies lying side by side in the tall grass. The men were dressed in formal suits and raincoats, despite the warm weather. On their faces were crude lead masks. Beside them lay a notebook with cryptic instructions, an empty water bottle, and a packet that once contained towels. There were no signs of violence, no struggle, no obvious cause of death. What should have been a routine police investigation became one of Brazil’s most enduring mysteries, involving strange lights in the sky, amateur electronics experimentation, and a puzzle that remains unsolved nearly 60 years later.
The Discovery
Eighteen-year-old Jorge da Costa Alves was flying his kite on the afternoon of August 20, 1966, on Vintém Hill in Niterói, a city across Guanabara Bay from Rio de Janeiro. The hill was a popular spot for kite flying, offering clear skies and steady winds. As Jorge climbed higher up the hill, he noticed something unusual in the grass about 10 meters from the path.
Two men lay on their backs, positioned side by side with an eerie precision. They were well-dressed in dark suits, white shirts, and raincoats—formal attire that seemed entirely out of place for a hillside in the Brazilian summer. But what truly frightened Jorge were their faces: each man wore a strange mask made of lead, with eye openings cut roughly into the metal.
Jorge ran down the hill to alert authorities. By the time police arrived, it was growing dark. In an inexplicable decision that would compromise the investigation, the officers decided to return the next day rather than secure the scene immediately. By the time they came back on August 21, crucial evidence may have been lost, contaminated, or removed.
The Victims
The dead men were soon identified as Manoel Pereira da Cruz and Miguel José Viana, both electronic technicians from Campos dos Goytacazes, a city about 175 miles northeast of Rio. They were experienced electronics engineers who repaired televisions and radios, and occasionally dabbled in amateur radio and electronics experimentation.
Manoel, 34, was married with children. Miguel, 32, was also married. Both were described by friends and family as responsible, intelligent, and not prone to reckless behavior. Neither had a history of mental illness, drug use, or involvement in criminal activity. They were ordinary men with ordinary lives—until August 17, 1966.
The Timeline
Investigators pieced together the men’s final days through witness interviews and receipts found on their bodies:
August 17, 1966, 2:30 PM: Manoel and Miguel left Campos dos Goytacazes by bus, telling their families they were going to São Paulo to buy electronics supplies and a car. They bought two raincoats before boarding, despite the forecast calling for sunny weather.
3:00 PM: The bus conductor and other passengers later reported the men were calm and conversed normally during the journey. They got off the bus in Niterói, not São Paulo as they had told their families.
4:00 PM-6:00 PM: Witnesses reported seeing two men matching their descriptions in Niterói, purchasing a bottle of mineral water and at one point asking directions to a specific address. One witness, a bar owner, remembered them because one of the men seemed nervous.
6:30 PM (approximate): The men apparently climbed Vintém Hill. It’s unclear if they went alone or were meeting someone. The site where they were found offered a clear view of the sky and surrounding area but was isolated from main paths.
August 17-20, 1966: At some point during this period, both men died. Their bodies weren’t discovered until August 20, three days later. By the time investigators arrived on August 21, decomposition had advanced significantly in the tropical heat.
The Evidence
When police finally processed the scene, they found several items arranged near the bodies:
• Two crude masks made of lead, with rough eye-holes cut into them
• An empty bottle of mineral water
• A packet that once contained towels
• A small notebook containing handwritten instructions
• A receipt from a bar in Niterói
• Some cash and personal items
The notebook contained the most intriguing evidence. Written in Portuguese, the notes appeared to be instructions for some kind of procedure:
“16:30 be at the agreed place. 18:30 swallow capsules, after the effect protect face with metal masks await signal to show itself.”
This cryptic message suggested the men had planned whatever happened to them. They had an appointment (“the agreed place”), were meant to ingest something (“swallow capsules”), would experience some “effect,” and were then to put on the lead masks and wait for a “signal.”
The implications were disturbing. Had they been instructed by someone else? Were they participating in an experiment? What were the capsules? What signal were they waiting for?
The Autopsy Problem
Here the investigation hit a critical obstacle: the autopsies were incomplete and ultimately inconclusive.
Due to the advanced decomposition and limited forensic capabilities in 1966, the medical examiner could not definitively determine the cause of death. The bodies’ internal organs were too degraded for meaningful toxicological analysis. No samples were preserved for future testing.
The official autopsy report, such as it was, noted: “Cause of death: unknown. No evidence of external trauma or violence.” The toxicology report was listed as “inconclusive due to decomposition.”
This meant that investigators couldn’t determine if the men had been poisoned, overdosed on drugs, died from some chemical exposure, or succumbed to some other cause. The crucial question—what killed them?—remained unanswered.
The UFO Connection
The case took a bizarre turn when investigators began interviewing witnesses from the area. Multiple people reported seeing strange lights in the sky over Vintém Hill on the evening of August 17—the day the men arrived in Niterói.
A group of witnesses, including members of the coast guard, reported seeing an orange, glowing object hovering over the hill around 7:30-8:00 PM. The object allegedly remained stationary for several minutes before shooting away at high speed. Other residents reported similar sightings of unusual lights in the days before and after.
These reports, combined with the lead masks and the notebook’s reference to waiting for a “signal,” led to immediate speculation: had Manoel and Miguel been attempting to contact extraterrestrial beings? Were they victims of a UFO encounter?
Brazil in the 1960s was experiencing a wave of UFO sightings, and the possibility of alien contact was taken seriously by many. The lead masks, some theorized, were meant to protect against radiation or some otherworldly energy.
Theories
The Spiritual Experiment Theory: Investigators discovered that Miguel José Viana had been involved with spiritist and occult groups in Campos dos Goytacazes. In Brazil, spiritualism has a significant following, with various groups practicing different forms of contact with spirits or seeking transcendental experiences.
Some occult groups in the 1960s believed that certain locations had spiritual significance or could facilitate contact with higher dimensions. These groups sometimes used hallucinogenic substances to induce altered states of consciousness.
The theory suggests Miguel convinced his friend Manoel to participate in a spiritual experiment: they would take psychedelic or hallucinogenic capsules (possibly containing substances like LSD, which was legal in Brazil until 1966), wear lead masks to “protect” themselves from spiritual or electromagnetic energies, and attempt to achieve transcendence or contact with other planes of existence.
Under this theory, the men died from an overdose of whatever substance they ingested, possibly combined with the heat and physical stress of wearing heavy masks. Their raincoats were meant to keep them dry in case of rain while they waited for the “signal”—perhaps a celestial event or specific time.
The Electronics Experiment Theory: As electronic technicians, Manoel and Miguel had access to and knowledge of various electronic components, some of which contained toxic materials. In the 1960s, television repair involved handling tubes containing toxic metals, capacitors with dangerous chemicals, and other hazardous materials.
Some researchers suggest the men may have been experimenting with building electronic detection devices—possibly trying to detect radiation, electromagnetic fields, or even radio signals they believed came from UFOs. The lead masks might have been crude radiation protection.
They may have accidentally exposed themselves to toxic materials (heavy metals, radiation, or toxic gases from faulty electronic components) and succumbed to poisoning. The “capsules” might have been vitamins or minerals they believed would protect them from radiation exposure.
The Murder Theory: A darker theory suggests the men were murdered, and the scene was staged to look like a bizarre suicide or accident. The cryptic note could have been forced upon them, and the lead masks placed after death.
However, this theory has problems: there was no evidence of struggle, no defensive wounds, and no clear motive. Both men’s valuables remained with them. Why would someone stage such an elaborate scene?
The Drug Experiment Gone Wrong: Perhaps the simplest explanation: the men obtained powerful drugs or psychedelics, went to a remote location to experiment with altered consciousness, and miscalculated the dose. They died from overdose or from a combination of drugs, heat, and dehydration.
The lead masks might have been based on a misunderstanding of how to “protect” oneself during a psychedelic experience, possibly gleaned from occult literature or paranormal theories popular at the time.
Similar Cases
Disturbingly, the Lead Masks Case was not unique in Brazil during this period. Several similar incidents occurred:
In 1962, four years before the Vintém Hill case, an attorney named Dr. Sebastião Reis was found dead in Tijuca Forest, also near Rio. He wore similar protective equipment and was found with electronic devices and strange notes referencing experiments with “cosmic energy.”
In subsequent years, other bodies were found in isolated locations with similar characteristics: protective masks, notes about spiritual or cosmic experiments, and no clear cause of death.
These cases suggest there may have been an underground movement of individuals experimenting with altered consciousness, spiritual transcendence, or amateur science in remote locations, sometimes with fatal results.
The Reopened Investigation
In 2012, the case was partially reopened when Brazilian investigator Carlos Alberto Pereira obtained previously unreleased police reports. These documents revealed:
• The police had identified a third man, seen with Manoel and Miguel on August 17, but this person was never found or officially identified
• Several witnesses reported that the men asked specific questions about the best location to “see the sky” and whether any unusual phenomena had been observed in the area
• A pharmacist came forward (decades late) claiming someone matching one of the men’s descriptions had asked about purchasing large quantities of a sedative drug days before the incident
However, without bodies to re-examine (they were buried decades earlier), without preserved tissue samples for modern toxicology, and with most witnesses dead or memories faded, the reopened investigation yielded no definitive answers.
The Cultural Impact
The Lead Masks Case has become embedded in Brazilian popular culture as one of the country’s most famous unsolved mysteries. It has inspired:
• Numerous books and documentaries
• Television series episodes featuring the case
• Academic papers on forensic failures and unsolved cases
• Ongoing debates in Brazilian UFO research communities
Vintém Hill itself has become something of a pilgrimage site for paranormal investigators, with some claiming the location has unusual electromagnetic properties or heightened UFO activity.
What Really Happened?
The most likely explanation, supported by the available evidence, is that Manoel and Miguel were involved in some form of amateur experiment—possibly spiritual, possibly scientific, possibly both—that went fatally wrong.
They likely ingested capsules containing either psychedelic drugs or substances they believed would facilitate an altered state of consciousness or protection from perceived radiation. The lead masks were meant to shield them from whatever energies or signals they expected to encounter.
They died from poisoning—either an overdose of whatever they ingested, or possibly from toxins in the materials they used to construct their masks or other equipment. The decomposition prevented forensic confirmation, but the lack of violence or struggle suggests they lost consciousness relatively peacefully, possibly never realizing they were dying.
The “signal” they were waiting for may have been a psychological expectation, a misunderstood instruction from an occult group, or simply the effects of whatever drugs they had taken.
The bodies of Manoel Pereira da Cruz and Miguel José Viana were buried in their hometown, leaving behind grieving families and unanswered questions. What drove two ordinary men to climb a hill wearing lead masks and wait for a signal that never came? Were they victims of a tragic misunderstanding, pursuing enlightenment or knowledge through means they didn’t fully comprehend? Or did something unexplained really happen on Vintém Hill on that August evening in 1966—something we still don’t have the framework to understand? The hill overlooks the bay today, unchanged, indifferent to the mystery it witnessed. And somewhere in the archives of Brazilian police records, a notebook page remains with those enigmatic words: “await signal to show itself.” The signal, whatever it was, never came. Or perhaps it did, and the two men answered it in the only way they could—by stepping across a threshold from which there is no return, taking their secrets with them into the darkness, their faces hidden forever behind masks of lead.