CONTENT WARNING: Story contains graphic descriptions of a deceased woman and the manner her body was found.
ST. PETERSBURG, Fla. (WFLA) — During the process of cremation, the human body is burned in a fire between 1,400 to 1,600 degrees, Fahrenheit. In July 1951, a woman in St. Petersburg died under mysterious circumstances and burned at temperatures of at least 2,000 degrees, according to archived documents from the FBI.
Her name was Mary Reeser, and she allegedly died in her sleep at an apartment on Cherry Street. A cause of the fire was never officially confirmed, leaving her death still a mystery 71 years later. She was 67.
Reporting in the St. Petersburg Times the day of the incident said the cause of the “white-hot” fire was a mystery. According to a description in the St. Petersburg Times in 1951, Reeser’s body had “disintegrated” due to the fire, but that the apartment around her did not sustain enough damage for what funeral directors said the fire would have been capable of.
Five days after beginning their investigation, the St. Petersburg Police Department sent a box of evidence to the Federal Bureau of Investigation. According to the Times’ reporting, “portions of the apartment rug, smoke samples, rubble from the walls and floor and segments of the chair in which Mrs. Reeser was last know to be sitting” were all included in what was sent to the FBI for analysis.
FBI files preserved by third-party organization “The Black Vault” contain the letter sent by St. Pete Police Chief J.R. Reichart asking for their assistance in the case, as well as investigative records and details of the scene where Reeser was found.
The condition of Reeser’s body was also of concern. Files from the case describe how Reeser was found.
The official report from the archive reads, “Body was all burned but the knees to the feet were all right. Black suede shoes were not burned.” The files report that all that remained of Reeser after the fire were a shrunken skull, part of her spine, and part of her left foot still in a suede shoe.
Within the FBI document, a report on Reeser’s death by a University of Pennsylvania professor said in his experience, only certain conditions could leave a body the way Reeser was found.
“Once the body starts to burn,” the FBI report said, “there is enough fat and other inflammable substances to permit varying amounts of destruction to take place. Sometimes this destruction by burning will proceed to a degree which results in almost complete combustion of the body.”
How Reeser came to catch fire was not made entirely clear, though the FBI did submit a theory.
The file said Reeser was known to take “Seconal tablets before going to sleep.” Seconal is a barbiturate sleep medication. She was also known to smoke cigarettes.
“Due to the fact Mrs. Reeser had taken a considerable amount of sedatives at night, and we do have evidence that she told her son, Dr. Richard Reeser, that she had taken two sedatives at 8:00 P.M. and was going to take two more, there is every possibility that Mrs. Reeser while sitting in the overstuffed chair, could have become drowsy or fallen asleep while smoking a cigarette, thus igniting her clothes as at that time she was clad in a rayon acetate nightgown and a housecoat,” the report reads.
Rayon is a semi-synthetic fiber which is known to be “highly flammable,” according to studies by the University of Nebraska. The FBI report on Reeser’s death notes “the nightgown” worn by Reeser, “being highly inflamable, could have been ignited by a burning cigarette, causing immediate death.”
The report also indicated a lack of any accelerants, such as gasoline or petroleum. The document says “the greasy substance which saturated several of these specimens,” referring to evidence sent to the FBI, “was found to be human fat.”
Dr. Wilton Marion Krogman was brought in to aid in the investigation by St. Petersburg police, according to the file. According to Krogman’s report on Reeser, the condition of her remains did not fit with the heat that would have been necessary for such destruction, and he disagreed with some of the FBI’s findings.
However, Krogman’s publication said that the level of heat necessary to do so would not have left a skull intact at all, let alone shrunk it. He wrote that at 2,000 degrees Fahrenheit, “scarcely a bone that was not present and completely recognizable as a human bone” remained in cremations he had observed.
“Only at 3,000 degrees Fahrenheit, plus, have I seen bone fuse—or melt, so that it ran and became volatile.” He said at those heats, the bones would “sear, char, scorch, or otherwise mar or effect anything and everything within a considerable radius.”
Krogman’s study of the evidence, and his own academic research, fueled the mystery surrounding Reeser’s death. He noted that the room around her did not show signs of experiencing the same level of heat.
In the document’s “examination results,” the report said “the destruction of the deceased’s body which occurred in this case it is entirely possible that the body was consumed to the extent shown in the photographs and as indicated by bone fragments and other debris without aid of any such material as gasoline” because people don’t “generally” understand “the extent to which the human body can burn once it becomes ignited.”
According to the documents sent by St. Pete police to the FBI, the condition of the apartment Reeser was found was a mystery, partly due to the body’s condition compared to its surrounding environment.
The documents provided to the FBI said the room itself was largely untouched, but that it “showed signs of extreme heat on the ceilings, walls approximately 4 ft. from the floor. Plastic light switches had melted but floor plugs were unharmed.” A clock in the room had “stopped at 4:20 a.m.,” according to the file.
When asking the FBI to help on the case, Chief Reichart said, “We also request any information or theories that could explain how a human body could be so destroyed and the fire confined to such a small area and so little damage done to the structure of the building and the furniture in the room not even scorched or damaged by smoke.”
During their examination of the evidence, the FBI said there was “no indication” that an electrical surge or lightning storm had struck the building to set Reeser on fire.
The exact cause of Reeser’s death remains a mystery. Some theories proposed spontaneous human combustion, though the investigative files said there was “absolutely no evidence from any of the cases on record to show that burning of this nature occurs other than when the body is ignited by some external means.”
The phenomenon, though dramatic, has never been conclusively or scientifically proven to be possible outside of fiction.
Reeser was laid to rest at Chestnut Hill Cemetery in Pennsylvania.