Lucy Letby
BBC Reporter Judith Moritz (reviewing social media posts on a ostentatiously product-placed MacBook):
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The JC Sounds Off™
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“We’ve found a witch. May we burn her?”
- — Peasant, Monty Python and the Holy Grail
“There are ways of telling she’s a witch”
“Sparky, full of fun, popular — she looks like the life and soul of the party in these photos. I don’t know what Britain’s most prolific child killer should look like. I’m pretty sure it’s not this, though.
“She comes across as — mousy; a bit normal — you can’t really marry that with the enormity of what she’s been accused of.”
This fits two profiles: either this is some cold, callous, monstrous psychopath — or a perfectly ordinary young woman. You know — a sparky, fun, popular young woman. The life and soul of the party.
On herd minds, groupthink and narrative bias
Lucy Letby’s case is in the news and those internet citizens who have taken more than a passing interest have divided into opposing camps: a large preponderance for whom she is a cold-blooded monster, and a small band who, based on statistics, have questioned the safety of her conviction. Some of those have spilled over into the conviction that Letby absolutely did not wilfully kill anyone.
JC has his opinions, which we will get to, but the first step is to keep an open mind. Once you firm a view anything can be shoveled into suiting your narrative, or weeded out as being irrelevant to it. This opposite of confirmation bias we call ignorance bias, for want of a better expression. Both can be used in service of either certainty: that Lucy Letby is a serial killer, or the victim of a grave injustice. Both standpoints are equally emotive. There is no comfortable centre to hold here.
We are at the intersection of at least four discrete fields of intellectual enquiry here: law, epistemology, statistics and ethics. They are not commensurate — they each have their own rules, customs and institutions and authority in one does not commute to the others. In a perfect world their outcomes would converge, but the world is not perfect. There will be circumstances in which the correct legal outcome is not morally right, the correct moral outcome is not borne by the statistics, the statistics are at odds with our knowledge, and vice versa. There is little wonder good people get upset.
You cannot but frame your understanding of the scenario through one or other of those prisms. There is no transcendent, neutral frame of reference by which the others may be judged. Without a framework the territory is random, incoherent noise. But enough about cognitive relativism.
But to say that the scenario one that unusually uncertain, and the prospect of consensus is unusually low.
Substance, form and process
The first thing to bear in mind is the difference between the substantive — the wilful morally unjustified ending of a life (this is an ethical frame of reference), the formal — the commission of the act of murder as defined in law (in some ways an ethicist’s map of the territory), and the procedural — the process gone through to determine whether a murder was committed.
These are different questions, with different considerations, and it is important they are not confused. A person who murders unobserved in cold blood, leaving no evidence, and without motive cannot be convicted of murder. The procedural element fails. A person who kills in cold blood, before witnesses but in demonstrable, reasonable self defence, cannot be convicted of murder because the formal elements are not met.
Where there is no eye-witness evidence the form and procedure becomes all the more important.
In Lucy Letby’s case there is no direct evidence. This means it is logically possible she did commit the murders, and logically possible she did not. The question of whether she should be convicted comes down, at some point, to an estimation of probabilities. These inform how “sure” one can be about the proposition “defendant murdered victim”.
This is a murder case with an unusual range of unknowns. It is unclear whether there was any murder at all. The deaths could have been innocent, and they could have been culpable to some legal standard short of murder (negligence, for example)
If you conclude that “foul play” (including negligence) is at work there is then the question of who did it. Did other personnel have an opportunity?
Each of these enquiries requires an answer “beyond reasonable doubt”. If a victim dies in the presence of a single person with a means and motive, such that if the death was intentional there is no other possible suspect, if there is a reasonable doubt as to the death being natural — even if it probably was not — there can be no conviction.
“Once is happenstance. Twice is coincidence. Three times is enemy action.” — Ian Fleming, Goldfinger (1959)
Here is where a sequence makes a difference. One such occurrence might be improbable, five occurrences extremely improbable, 500,
So
What are the percentages of serial killers with history of broken homes, physical or sexual abuse, and mental illness? What percentage are female?
“God complex”
Killing people is not evidence of a God complex. The basest criminal can take life. Bringing people back to life — that is evidence of a God complex.
Evidence
Insulin “smoking gun”
In two cases (Child F and Child L) lab tests indicating high levels of insulin without accompanying c-peptide, which is prime facie evidence of administered insulin (naturally occurring insulin is accompanied by c-peptides; artificially administered insulin is not). Insulin was not prescribed for either infant. If it was true that insulin was added without prescription this is evidence of actual human agency in these two episodes.
The defence team accepted the prosecution’s claim that insulin was added to parenteral nutrition bags and it was presented to the court as an agreed fact.[1]
- The test in question was not reliable for factitious insulin. From the label:
“Please note that the insulin assay performed at RLUH is not suitable for the investigation of factitious hypoglycaemia. If exogenous insulin administration is suspected as the cause of hypoglycaemia, please inform the laboratory so that the sample can be referred externally for analysis.”
- The test results seem to indicate very high levels of insulin: 4657 pmol/L is about four times a dangerously high level in an adult.[2] While, yes, this is what you might expect a murderer to try to do —
- Both babies recovered: You might expect premature babies registering such high insulin levels — four times a critical level for an adult[3] — might have at least caused a fuss at the hospital. But not only did the babies make a full recovery, with no record of hypoglycemic coma, but —
- No-one even noticed the high insulin in their tests until 2018: That is, three years after the babies made a full recovery. If you are looking for a res ipsa loquitur about these events, can we suggest that this is as indicative of negligence in the clinical staff administering the test, or the self-professed unreliability of the tests for detecting factitious insulin.
The Texas sharpshooter
See the TriedbyStats website: Over 730 shifts, with 38 “suspects” If you self-select one
The victim’s families
There are unquestionable victims here: the families. If Lucy Letby wasn’t responsible then this was either an unavoidable accident, in which case, there is no closure, or there is another culpable explanation — an alternative murderer seems extremely implausible — but medical misadventure of some kind is not. Difficult
The post-it note
Everyone seems to accept the notes are highly inclusive and of little evidential value.
“The ramblings of someone under extreme psychological pressure.”
Resources
Online
- That New Yorker Article (choose your own snapshot from the Wayback Machine)
- Mephitis - The Lucy Letby Case May In Time Be The Story Of The Century
- TriedbyStats
- The Insulin ‘Evidence’ in the Lucy Letby Trial. Criminal Justice in England: Disagreeable Facts
Podcasts
- We need to talk about Lucy Letby (Peter Elston and Michael McConville podcast)
- The Trial of Lucy Letby (Daily Mail podcast)
See also
References
- ↑ Science on Trial
- ↑ There is plenty of online angst about whether the level recorded was abnormally high or absurdly high, such that such a level had never been witnessed in medical history: let’s go with abnormally high.
- ↑ See: Very Well Health: Hyperinsulinema (High Insulin Levels).