Many historians agree; Spontaneous Human Combustion (SHC) was first documented in early texts such as the Bible. Scientifically speaking, these accounts are too old. Also not first hand accounts and it is difficult to consider it reliable evidence.
Last 350 years
Over the past 350 years, there have been more than 400 reports of persons burning to a crisp for no apparent reason.
The first reliable historic evidence of Spontaneous Human Combustion appears to be from the year 1673, when Frenchman Jonas Dupont published a collection of Spontaneous Human Combustion cases and studies entitled De Incendiis Corporis Humani Spontaneis.
Dupont was inspired to write this book after encountering records of the Nicole Millet case. On February 20, 1725, her husband found the remains of Nicole Millet. Curiously, the chair was hardly singed. A phenomenon often seen in SHC. Nicole Millet was a heavy drinker. Although the married couple went to bed together. During the night, Nicole got up because she could not sleep. She went to the kitchen to warm up a bit. Jean Millet, the husband, went back to sleep. At two in the morning, Jean Millet woke up again because of a foul smell. He got up to investigate and when entering the kitchen to find the source of the smell.
There he discovered the smoldering remains of his wife. There was little left of the Mrs. All that remained were some of her intestines, a part of her head and parts of her legs. The rest was a pile of ashes. Objects in the vicinity however, remained unscathed.
After primary investigations, Mr. Millet was arrested. Presumably, Jean had murdered his wife and cremated her corpse to hide the evidence of his actions. The idea was that he had traded in his wife for his employee; a young chamber maid. The murder case was taken all the way up to higher court. There, the judgment was that Nicole Millet was not murdered. Setting Jean Millet free.
This whole ordeal did leave marks on Jean Millet. The stress and time spent in jail made him sick. The rest of his life was spent in hospital.
in which a man was acquitted of the murder of his wife. The court was convinced that she had been killed by spontaneous human combustion.