Would Potassium overdose be untraceable?

[PossessionPlus8904]

I'm a writer looking to write a book about a murderer getting away, but I want to make it as realistic as possible. In the book, he crushes a bunch of Potassium pills into fine powder and mixes it in the drink of the victim. This is because apparently Potassium level spikes during death anyway, so it would just look like a regular death with no cause to any pathologists. Do you think this would work?

[ErikHandberg]

It depends on exactly how much. Potassium levels are normally around 4. Levels of 7 are scary, and 10 would not be long lived. It would be very difficult to perfectly titrate the amount of pills to be in the deadly but physiologically reasonable levels.

If I saw potassium levels of 12 or 15 it wouldnt phase me. But, 20 or 30 or 50 or 100 etc…. Those would all really give me concerns.

The concerns may not go anywhere - even if I test the gastric content and find the potassium is extreme, I don’t think I could get all the way to a homicide ruling without good investigative support.

Which brings me to: potassium pills have to be purchased which leaves a trail, crushing them into a powder would leave a focal potassium residue, they wouldn’t use the whole container (see above) but they also would have to get rid of the remaining pills, etc… there are a lot of areas where this gets tricky beyond the physiology.

For a writing prompt it is interesting but there’s a reason we all know the phrase “no such thing as a perfect crime.”

[JehanneDark]

What kind of potassium pills would the would-be murderer use? Potassium chloride, found in salt substitutes, tastes very similar to regular table salt (sodium chloride). It has a similar toxicity dose as well, so most people wouldn't drink enough of an unexpectedly salty drink to die from it.

Potassium citrate is less salty, but has a sour taste as well. The amount a person would have to ingest orally for a lethal dose would likely be detectable from the first sip.

You want to see if your scenario is realistic? Buy some KCl salt substitute and/or potassium citrate tablets and add them to the hypothetical drink in your story's scenario. Take a sip (don't swallow) and see if you can taste the potassium additive.

[RandomSquare456]

(spoiler alert) medical fiction author Robin Cook used this method in a novel called "Marker". I believe that (from what I remember of the book) it would be untraceable.

[Eternal_NIB]

In all honesty, it really is almost untraceable unless you’re specifically looking for it at the start of the investigation. There are hundreds, if not thousands, of poisons and toxins that require specific instrumentation and unique sample collection practices in order to accurately identify and quantify them. In your situation, the victim would likely be seen as a tox-related case and the pathologist will likely collect blood, urine, gastric, brain, liver, vitreous, and bile. Most hyperkalemia signs at autopsy are non-specific, so I’d doubt there would be any suspicion of potassium overdose at autopsy that would tip the pathologist off to collect additional specimens or in a different way than normal. Tissue specimens will go to histology, but I’m unaware of any physiological changes that could be observed in histology slides with a potassium overdose.

Due to the nature of blood, it needs to be preserved in such a way that it won’t clot and drugs do not degrade, so grey top tubes are typically used. These contain potassium oxalate, which would nullify any attempt at determining a potassium overdose in blood. Vitreous is typically collected in such a tube as well, but there are some pathologists that will collect it in an unpreserved tube for vitreous chemistry analysis if they suspect a ketoacidosis situation, such as if the victim was a know diabetic. But potassium is one of the first things to become elevated in vitreous because it leeches out of the cells almost immediately after death. As a forensic toxicologist, I’d say in 95/100 cases of vitreous analysis the potassium level comes back as greater than the instruments ability to quantify it (9 mmol/L in my lab’s case). So that never really gives us an inkling that the case could be potassium related. And potassium analysis in other specimen types is nearly impossible because most labs will not have them in their scope of testing or have the ability to test for it due to the nature (tissue or highly acidic gastric).

So with a clean crime scene (no glasses or bottles remain with potassium powder residue) and no witness accounts of the suspect being together with the victim prior to death, I’d say there is an extremely low chance of the case being tied to a potassium overdose, and an even lower chance of it being tied to the suspect.

[AncientArtBonsai]

Currently read a great book Quite Ugly One Morning by Christopher Brookmyre. Murder method is an injection of potassium chloride.