Cannibalism - #24: DNA

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TRANSCRIPT OF EPISODE: Cannibalism (munching) “could you eat a whole human being? With the help of a doctor, a scientist and a chef, I set out to see if it’s possible. Cannibalism: part twenty-four – DNA”. (burp)

No matter how thorough a cannibal cleans up, it’s the tiniest body part which will always convict them.

2007, Canada, Robert Pickton was convicted of murdering 26 women, having ground their bodies in a meat grinder and fed it to his pigs, or (it is claimed) to the public. Forensic anthropologists used soil sifters as all that remained were tiny traces of human remains, and without a body, the case may have collapsed. But with the DNA of 80 profiles found on his jacket, boots and freezers, he was sentenced to life, and later admitted “I killed 49. I planned an even 50, but I got caught as I got real sloppy”.

Every human is 99.9% genetically identical, but that 0.1% difference comprises of a 3 billion letter long genetic code with its combinations so infinitesimal that even identical twins are genetically different. And with our 36 trillion cells, each containing 6 feet of DNA, if our genome were stretched into a single thread, it would reach to the sun and back ten times, yet it only weighs six one-trillionths of a gram.

2005, Sweden, Lennart Persson stabbed, drank the blood and ate a breast of one of two victims killed seven months apart, and yet all it took was a few microscopic drops of blood to convict him.
The oldest DNA discovered is so far over 2-million-years-old, with the DNA of Richard III able to identify his remains after 540 years underground. When we die, our DNA lives on in dead cells, but when DNA loses its purine base, known as depurination, it breaks apart at an atomic level. If buried it can last as long as 10,000 years, exposed to the elements it can last just a few weeks, but subjected to stomach acids, after just 2 hours, 80% of the DNA is destroyed, and within a day, almost all of it had dissolved.

If a serial killer buys sulphuric or hydrochloric acid to dispose of a body, that leaves a trail of clues, but with 99% depurination happening at 37 degrees Celsius - the temperature of our stomach acid - it’s as efficient as a liquid crematorium and it’s entirely untraceable, as well as being natural and legal.

The problem is that before a cannibal even feasts on Steve, that day, he’s shed 1 to 5 eyelashes, 50 to 100 hairs, 10 litres of sweat, it’s estimated that he’s left 140 usable fingerprints, and has sprinkled 500 million dead skin cells everywhere he’s been.  

1975, Pennsylvania, Lindy Sue Biechler was found with 19 stab wounds and the knife embedded in her back. The police had the suspect’s DNA, but with no name, the case went cold. Until 2022, when that DNA was uploaded to a genealogy website, and finding his relatives, Police surveilled 68-year-old David Sinopoli, and getting his DNA off a discarded coffee cup, he was convicted 48 years after the murder.

So paranoid are serial killers, that in 2003, when South Korean serial killer and self-confessed cannibal dubbed ‘The Raincoat Killer’ cut himself opening a safe, he burned the house down to destroy his DNA.

We leave traces of ourselves everywhere, without even thinking about it.

We imagine cannibals sinking their teeth into a thigh and tearing it apart, and although our palaeolithic ancestors had larger jaws and sharper canines to do just that, as omnivores who use tools to cut meat apart and cook them to make them often, evolution has made us a much less efficient apex predator.

Therefore, a cannibal has a problem that a serial killer doesn’t. A survey of dentists stated 87% of patients arrive with food (often meat) stuck between their teeth, which may be embarrassing for us, but as evidence of cannibalism - with it pointless to extract digested meat from a stomach and no use once it’s been expelled - the cannibal’s own saliva will protect that DNA from any regurgitation acids.

In the case of Karl Denke, the Cannibal of Münsterberg, almost a century after his crimes, DNA tests are being used to trace and authenticate the 30 to 40 victims he cannibalised and sold at the market.

The problem is, even those of us who aren’t cannibals, are mucky buggers in our daily lives. And if you think that some of these facts about cannibalism have been unsettling, get ready to be grossed out.

In Britain, just once a year, 36% of people wash their bedsheets and 18% their jeans, 25% of men wash their undies after five wears compared to 55% of women, with 6% of women washing a bra after 10 washes. 

I mean, how can a cannibal hide the evidence of a crime, if we can’t hide the evidence of a pizza?
To cut up a body requires knives, saws and sinks, and although Robert Pickton’s farm was a forensic nightmare, the average person’s kitchen is no better. In a study of 1000 people by a British kitchen retailer, 13% of sinks are only cleaned once a month, 4% of people never sanitise their worktops, 8% are 'unlikely' to clean a chopping board before or after cutting meat, and with vomiting being very possible in a cannibal as humans are toxic, studies show that your sink has more E-Coli than your toilet.

But before a cannibal has committed a crime, the evidence to convict them may already be out there.

In 2005, Dennis Rader alias ‘BKT’, a sadistic serial killer of at least 10 people in Kansas was arrested. His killing spree had gone silent for 14 years and as the Police only had circumstantial evidence of his guilt, the only way to prove it and stop the new killing spree he was threatening to commit was to get a sample of his DNA, or that his daughter whose DNA they retained by subpoenaing her pap smears.

So although, a long laborious task, digesting a body may be the most efficient way to ensure a cannibal leaves no evidence of their crime. But only if (pardon the pun) they’ve got the stomach to do finish it.

Join me tomorrow as we tick off all of the body parts a cannibal probably didn’t know existed.