
This is part five of a true series of stories about a surreal and unsettling medical experiment in Mexico City in 2017. You can read the other parts here in case you missed them:
03: A murder ignored
EXORCISMS WORK BEST, ACCORDING TO TRADITION, if they are a surprise. Like interventions.
Dr. Mosso was fully aware that his experiment was already hazy around the edges. That his fellow scientists would laugh at the idea of conducting an exorcism under laboratory conditions to try and see good, or God, or whatever we call it, defeat evil.
It was too much of an additional risk to let Maria in on his planned experiment, lest he prepare the demon inside her for what was to come and skew it further. So he told her that he wanted her to undergo a normal MRI scan, without telling her what for, and set the date for April 6, 2017.
On that day, with the approval of Maria’s parents, he gathered his team at a specialist cancer hospital, in a small private room dominated by a large General Electric MRI scanner — essentially a mechanized gurney and a mechanical tube in the midst of a magnet assembly just big enough to contain a person.
The machine would use magnetic fields and radio waves to produce a detailed picture of Maria’s soft tissue. Specifically, her brain. It was linked to a control room on the other side of a glass partition window. Lights and cameras poked through a tile ceiling to illuminate and capture the scene.
More than a dozen people tried to find space around the machine and in the control room. They included the original team that designed the experiment: Mosso, Dr. Castaneda and a gynecologist. A neuropsychologist, a neurosurgeon, a diagnostic radiology physician and two radiology technicians would administer the scan and interpret its results. Maria’s parents and an aunt wanted to observe. And hidden nearby was Father Cuitlahuac, ready to begin the exorcism as soon as Maria was securely inside the machine. They waited.
Maria entered unsuspecting, in patterned athleisure pants, hospital slippers and a light blue hospital gown. The radiology team connected her to monitors with snaking cables, clips and pads. She lay down on the gurney and was drawn inexorably into the interior.
In the control room she began to appear as a series of disconnected fragments of data. An outline of a human body showed what the machine was scanning. A grid of six rectangles showed how it was doing so. And the real-time MRI appeared in the top right corner of a computer screen, ghostly and unknowable, like a moving X-ray. A separate monitor tracked her heart rate, blood pressure, pulse oximetry and temperature.
The technicians gathered baseline data, and waited, and watched through the yellow tint of the control room window. Then Father Cuitlahuac emerged, in full ceremonial garb, a purple sash around his neck, wielding a Bible like a shield, and began to demand in a loud and commanding voice that the demons depart forever. The only part of Maria visible was her feet. They remained perfectly still.
The scanner showed nothing. No abnormal brain activity. But the atmosphere was strange. Tense. Maria's father complained of a sudden headache and a tightness in his chest. When Father Cuitlahuac finally stopped, there was silence. The gurney began to whir, and Maria drifted slowly out of the tube and back into the room. She vomited a foul and voluminous slime that looked and smelled, to the medical professionals present, like bile and gallbladder secretions.
Later Mosso got the final scans.

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They showed changes. But nobody quite understood what those changes meant. Maria herself experienced an intensifying of the symptoms of her possession. She began to black out unexpectedly. She vomited more often. A month later, her father suffered a massive heart attack. It began with the same headache and tightness in his chest he had experienced during the exorcism.
Mosso needed to get away. He went to the mountains his family came from, to restore his spirit. He was hiking when, after stopping to rest, he found a small brown snake in his pants — something he considered a very bad portent. Shortly afterward he fell and severely injured himself. In the aftermath of the accident he was brought to the exact same MRI scanner used in the exorcism.
He began to track all of the participants. Over the weeks and months after the experiment, 13 of them recorded misfortunes that they attributed to their experience with Maria. Father Cuitlahuac alleged that he was sexually harassed by two women in his church. The gynecologist present was accused, by her brother, of a crime she did not commit. Another doctor involved in the experiment decided suddenly to break up with her boyfriend of 10 years. A neuropsychologist, in charge of monitoring the MRI, disappeared for 49 days. She returned but will not say where she went.
There is, of course, no scientific explanation beyond coincidence and the human imagination. When I asked neuroscientists, they politely pointed out that the soul, and good and evil, and curses, are theological concepts, not scientific ones, and that it’s not possible to design an experiment or write an academic paper to measure them.
So I tried to contact Father Cuitlahuac. Was this a documented occurrence after exorcisms? Was there a biblical view of it? What was his explanation?
A colleague, Mariana Roa Oliva, went to his church, Rectoria del Espiritu Santo. It was on the other side of Mercado de Sonora, a large market that started decades ago in the narrow, winding streets to the southeast of the city. It is renowned for examples of brujeria, and for rows of statues, shrines and objects devoted to Santa Muerte and Santeria. Skulls, skeletons and grotesquely disfigured dolls were piled in stalls not far from beatific images of the baby Jesus and boxes of puppies and cages of birds packed so tightly they could not move.
It was Domingo de Ramos, the start of Holy Week, seven days before Easter Sunday. The church had just closed, but devotees were still selling palm decorations outside. Mariana asked two of the older women if they knew the priest.
They looked at each other in surprise. Father Cuitlahuac had died suddenly a little while back, they said. It was right after morning Mass. He had just taken off his robes. They didn't know the exact cause. ⸭
RAVI SOMAIYA is the founder of Bungalow. You can email him here.