The almost perfect murder

For decades, the hormone insulin, which is responsible for lowering blood sugar levels, was considered a perfect murder weapon because it was difficult or impossible to detect in forensic cases. For this reason, 38-year-old British nurse Kenneth Barlow chose insulin as his murder weapon to kill his 32-year-old wife Elizabeth. Unfortunately, this murder was the first in the world in which insulin could actually be detected. But first things first. It was May 4, 1957, when Kenneth called a doctor to his home in the northern English city of Bradford. He had found his wife, who was two months pregnant, drowned in her bathtub. He immediately drained the bath water and began resuscitation attempts, but to no avail. Kenneth told the doctor that Elizabeth had complained of feeling unwell, which is why she had decided to take a bath at around 10 p.m. As he himself was exhausted, he had already gone to bed. When he woke up an hour and a half later and Elizabeth still seemed to be in the bathroom, he decided to check on her. When he entered the bathroom, he found Elizabeth lying there dead. Her head had sunk into the bathwater. At first, the doctor didn’t find anything suspicious. But when he looked closer at Betty, he noticed her dilated pupils. To be on the safe side, he called the police. When they arrived, they found it strange that there were no water splashes on the floor and that the windows had not fogged up from the hot bath water. The detectives ordered an autopsy, as Kenneth was no stranger to them. A year earlier, his first wife had died unexpectedly. At the time, an anonymous caller had informed the police that she had not died of natural causes. However, nothing could be proven against Kenneth. In addition to the dilated pupils, the coroners noted that Betty still had water in the crook of her arm. If resuscitation had been attempted, there should not have been any water there. It was also strange that Betty had not noticed she was drowning. Had she been drugged with something? It seemed that Betty was unconscious when she drowned. The cause was suspected to be a lack of blood sugar, known as hypoglycemia. Since there was no organic cause for this in Betty, it could only have been caused by an overdose of insulin. However, a toxicological examination of the body was inconclusive. The doctors therefore performed a second autopsy after five days. During this autopsy, they found two injection marks on the buttocks that Elizabeth could not possibly have administered herself. They took tissue samples from these marks. These were stored in the refrigerator in order to perform an insulin test. In order to detect the insulin, the doctors had to carry out numerous experiments on over 1,000 mice, 90 rats, and 24 guinea pigs. This enabled them to determine the dose that caused hypoglycemic convulsions in the animals and to compare the probe with standardized samples containing the known amount of insulin. Measurable amounts of insulin were indeed found in tissue extracts. For control purposes, tissue samples were also taken from another corpse and treated in the same way. However, these were insulin-free. Kenneth, who had been unemployed for some time and had only been married to Elizabeth for 11 months, was now questioned by the police. Kenneth himself, who was considered a loving father who cared deeply for his 10-year-old son from his first marriage, testified that he had injected Elizabeth with ergometrine. This is a drug used in obstetrics, but also illegally to induce abortions. Like him, Elizabeth did not want to have a child. Toxicological tests revealed that Kenneth had lied, as the drug had tested negative in the toxicological examination. Kenneth Barlow was brought before the Leeds Assize Court in 1957 for the murder of Elizabeth Barlow. Experts confirmed that Elizabeth’s body contained a substance that matched all the typical characteristics of insulin. After 1.5 hours of deliberation, the 12 jurors unanimously found Kenneth guilty, and he was sentenced to life imprisonment on December 13, 1957. In 1984, after 26 years in prison, he was released on parole, confident that he had committed the perfect murder, but this turned out to be wrong.