William Peter Cook (Dec 17, 1924 – Oct 20, 1950): A Forensic Science Follow Up
by Sue Carney
December 06, 2021
I love a forensic science chat on Twitter, and it’s been a while since I’ve had one, so when Alice wanted to chat last weekend about an upcoming post on DCC, I was totally up for that. We were discussing fairly specific issues; Alice asked whether a stab wound to the chest might result in clothing becoming blood-soaked and queried the effects of a knife remaining in situ after a stabbing rather than being pulled out of the wound.
Such queries can be answered to a point, but inevitably lead to more questions, or at the very least, to conditions being attached to responses; ‘If this, then I might expect that’, or words to that effect. It’s almost impossible, in my opinion, to properly consider the significance of forensic science findings without some sort of context. Stephen Richey (@4N6Steve) put it best when he tweeted that the answer to most questions in forensic science is almost always, “It depends”. I couldn’t agree more.
Since these preliminary discussions, Alice has posted the case of William Peter Cook, (Dec 17, 1924 – Oct 20, 1950), a 25 year old US Navy veteran, whose death remains unsolved. I read this with interest, looking for a few more tantalising details to help in considering any forensic science-related aspects of this case, but overall, there is a paucity of information. As I jotted down my ideas, I thought, why not write them up in a kind of ‘forensic follow-up’ post… so here we are.
These are my thoughts on the case of William Peter Cook, from a forensic science perspective, likely focused towards forensic biology, although I will try to consider other relevant evidence types. They are not intended as suggestions of what could be done, but rather as a discussion of related issues, and the provision of a little forensic science information for those who might be interested in that sort of thing.
Conditioning Information
In considering possible forensic science intervention in a case, it’s useful to gather all the pieces of information about the case circumstances that might have any bearing on what may subsequently be found on exhibits in the case. Forensic scientists often refer to this as the ‘conditioning information’.
It’s important, when deciding what constitutes conditioning information, to include only reliable facts and not assumptions, speculation or unreliable pieces of information. For example, I would consider information about the timings of events (specifically the interval between these and the recovery of exhibits), the conditions (weather, location etc.), and details of what has happened, if they are known, to be vital pieces of conditioning information, but I would be wary of eyewitness testimony, which is frequently inaccurate, or other speculation. (That’s not to say that these are not useful to investigators, but they should not influence the interpretation of forensic science findings.)
This distinction between conditioning and other types of information is not straightforward. As forensic scientists, we are often provided with all manner of information in a case, and it can be tricky to get to the heart of the issue without being influenced by the peripheral details. It’s important therefore, to do this detailed thinking up front, and to document these thoughts in a case assessment, prior to starting any work on the case. This case assessment often leads to an examination strategy, which determines which exhibits will be examined for which types of evidence, and in what order. These details matter because searching for some evidence types may compromise others. There must be a plan before an exhibit bag is opened, and most crucially of all, we must have already considered the significance of any and every possible finding from that examination based on what we know about the case at that time. This could, and should be subject to change later, if new information comes to light.
So what do we know from Alice’s post, about the death of William Cook?
On 20 October 1950, an altercation took place on Hopkins Avenue and Marion Street, Brooklyn. William was stabbed at least once in the chest. Autopsy details tell us that his heart and left lung were perforated. Is that possible from a single stab wound or were there more?
William died that evening at King’s County Hospital. We know that medical intervention had included surgery and we’re also told that there were no indications of alcohol in his body at the time of his death.
Alice tells us that a belt, shirt, coat, sports jacket, and pants, purported to be from William Cook, were examined for blood and none was found. (I am assuming the pants are trousers — in UK English usage, ‘pants’ might more often be used to refer to underwear rather than trousers, so to avoid this ambiguity, in forensic science we tend to avoid the word, “pants”.)
Inevitably, consideration of these facts leads to more questions, and Alice picks up some of these in her post. This is the nature of a case assessment, and indeed, an investigation.
The Scene
We know little of the scene or the incident itself. There are no details of how many assailants were involved, whether anyone else was injured, or who witnessed the events. It’s not known whether William was conscious and gave his account of events, nor whether emergency services were called and took him to hospital, or he was transported by other means.
I was curious about the location of this incident. Google Maps suggests there is no longer a Hopkins Avenue in Brooklyn. Marion Street extends from Broadway at its eastern end to Malcolm X Boulevard at its western limit, interrupted near to its west end by the Brevoort playground and housing development, and intersected by numerous streets and avenues, none of which appears to be Hopkins Avenue. Malcolm X Boulevard can’t have been so named in the 1950s and there have undoubtedly been many other changes since then.

The Clothing
As Alice points out, there is no clear chain of evidence for the clothing items. If they are the clothes worn by William at the time of his death, then an apparent absence of blood is intriguing and raises several possibilities.
I must first mention the Report of the Bacteriological and Serological Laboratory, pictured in Alice’s post. This report is brief by today’s standards, despite the fact that there’s only so much that can be written about not finding blood. What interests me more as a forensic scientist is the small alteration that has been made in the report on the fifth line down, and the implications of this.
Prior to the alteration, this line appears to have been text reading ‘Organs used for analysis’. It’s clear that this is a pre-printed form because the text in the body of the report has been added by typewriter, which has also been used to amend this pre-printed line so to read, ‘Material used for analysis’. This suggests to me that perhaps the Bacteriological and Serological Laboratory did not routinely examine clothing, or if they did, then there was no specific form for that use at that time.
I wondered about the development of forensic science provision in New York and at what point the examination of clothing items such as these was carried out in laboratories specifically for that purpose, and indeed, using specific forms. A library search turned up an interesting dissertation, “The History of Forensic Science in the State of New York”, by Elke Hof-Kenyon in 2017 as part of her PhD at Albany. It makes interesting reading from an historical perspective, and I will send a copy to Alice. (Those with academic institutional access can download a copy via ProQuest .)
An Absence of Blood
The examination report suggests that no visible blood stains were found on the clothing but neglects to describe the search method; whether magnification or lighting were used. Blood stains might be readily visible on pale-coloured garments but would be more difficult to find on dark-colours. I was struck here by the absence of William’s shoes, which might have offered a variety of evidence types – not only blood, but other trace evidence. What could have happened to them?
The report continues by stating that the clothing gave “negative reactions to non-specific chemical tests for blood.” It’s not explained in the report exactly what this means, but ‘non-specific’ implies to me that these were tests carried out on areas of the clothing where there were no obvious stains, which was apparently everywhere. This fits with what would usually happen next in the examination of clothing items for blood: a screen of darker coloured garments using the same chemicals that would be used to test blood-like stains. (Indeed, the report mentions ‘reduced phenolphthalein’, which denotes a standard presumptive blood test called the Kastle Meyer or KM test.) Such a screen should systematically cover all the outer surfaces of relevant garments and might also include such areas as inside the pockets and cuffs for example, depending on who owns the clothing — injured party or suspect. It’s not clear from the report, the extent to which non-specific testing was conducted.
There are several possibilities raised by this lack of blood:
- These are not the clothes worn by William at the time of his death
- They are the clothes William was wearing at the time of his death, and blood is present but has not been found
- They are the clothes he was wearing, but no blood was transferred to them.
Option 1. cannot be ruled out since there is no chain of evidence. The report doesn’t make any reference to damage features on the clothing, which I’d expect to find, at least on the shirt, if the wearer had been stabbed in the chest. The presence of these would rule out option 1.
I suggested in our Twitter chat that If chain of custody were established, and there were no damage or blood, then this might suggest that William were dressed in these clothes after he was stabbed, possibly after death, but given the case circumstances I am now aware of, this suggestion does not seem to fit.
Damage
If William received emergency treatment, which seems likely since we also know he had surgery before he died, then his clothing might have been cut from him. If this happened, and we can’t be sure of standard hospital practice at that time, then this might have obscured any stab cut damage.
There’s much more that could be said about stab cut damage. If it is present on clothing, it can be used in considering whether particular weapons might have been used. I’ve worked on a number of cases where this was the issue, and a useful approach was to create test cuts with the weapons in question to see if the same damage features could be recreated. The more realistic the test, the more relevant the experiment, and there are various options here. Using meat as a medium to stab into was my method of choice (a roll of belly pork, wrapped in plastic wrap). Equivalents used in other cases include polystyrene cubes or ballistic gel.
Safety is important in these tests, and it’s good practice to wear a chain mail gauntlet on the stabbing hand, to avoid accidental injury, which can happen in stabbing, especially in a real stabbing, if a knife becomes heavily blood-stained and hence, slippery.
It’s also worth noting that stab cuts in clothing may not necessarily correspond with the location of stab wounds on the body, since clothing can move around during the course of a violent incident.
In my view, option 2 cannot be ruled out either. There have been plenty of instances of missed blood in forensic science, sometimes in the highest profile cases. The reasons are multiple and complex, and modern forensic science takes account of human limitations by implementing repeat blood searches as standard to mitigate the risks of missed blood. In my view, it’s extremely unlikely that this checking process was in place in 1950, although I can’t be sure of that.
Alice presents our discussions about option 3 in her post. It is possible that no blood was transferred to William’s clothing as a result of the stabbing. If the blade remained in situ, this could have staunched the blood flow, although there is no mention of a weapon being recovered. It’s also possible, depending on the type of blade and factors such as William’s position after he was wounded, that the majority of bleeding was internal. Stephen Richey recounted an example of this in our Twitter discussions; the case of a man who sustained a deep chest wound resulting in critical internal injuries with almost no outward signs. He was very lucky indeed to survive, and this was a great training case for medics, EMTs and forensic experts alike.
The Autopsy
Alcohol is often a driving factor in violent crime, so it’s interesting that it may not have been a factor in this case; there was no alcohol in William’s body when he died. On examining the alcohol report more closely, I noticed that the analyst was Alexander Gettler, who is often considered to be the “the father of forensic toxicology in America.”
We’re also told that William had no injuries to the scalp or brain. I’m curious as to whether he showed any defensive injuries on his hands or arms, or other injuries that might indicate the extent of the struggle that took place between him and his assailant(s). None are mentioned in the autopsy report, although further scrutiny of the autopsy report (pages not shown on DCC but kindly provided to me by Alice) reveals that William sustained abrasions to his left side above his second rib.
As I stated in chat on Twitter, I’m not sure whether the injuries to William’s heart and lung observed during the autopsy, could have been caused by a single stab wound or would have needed separate stabs. Two sutured wounds are mentioned in the autopsy report, one of which is described as an operative wound, in addition to mention of a stab wound to the back left. Despite this additional detail, it’s remains unclear to me whether there was more than one stab wound (could one of the sutured wounds also be a stab wound?) and the autopsy report would benefit from some ‘forensic medical translation’.
The characteristics of stab wounds; their size, shape, and appearance, can be useful in determining the type of implement used. I have worked on a case previously — a multiple stabbing— in which wound characteristics, in conjunction with fabric damage features on clothing, were used to assess whether a range of knives could have been used to cause specific injuries to the deceased. What was most interesting about this rare forensic medical/biology collaboration was discovering from my forensic medical colleague, that wound tracts are rarely longer than the total length of a blade, (unless the blade has been pushed into the body with force, causing marks from the hilt at the wound site) and unlikely to be narrower than the widest part of the blade (seems logical so far), so wound dimensions can be mapped against blade dimensions to either rule in or rule out putative weapons.
(For the geeks who need more: we plotted width of blade / wound by length of blade / wound tract. This produced a profile of the knife blade and a scatter plot representing individual wounds. Those wounds positioned below the blade profile could be excluded as being too narrow to have been made by the questioned blade. This approach is not perfect, because inclusion is never definitive, and the approach doesn’t take account of movement of a blade within a wound, thus increasing its size.)

When such data is also mapped to fabric damage features (remembering that this might be tricky — clothing can move, meaning that stab holes may not correspond to stab wounds) an extra layer of detail may be provided. What is interesting here is that, unlike skin and tissue, damage to fabric can be smaller than the widest part of a blade, because fabric can stretch and retract when a blade is removed.
Final Summing Up
As Alice points out, the age of this case suggests that whoever killed William Peter Cook is most likely dead by now, but that isn’t the point. Do any of these musings take this case forward? Maybe they’ll suggest a further line of inquiry or trigger a memory of some relevant detail. Even if they don’t, I hope this has been an interesting exploration of some aspects of forensic science that relate to the case, and good practice at case assessment. Sometimes the hardest part of an investigation is knowing the right questions to ask, and I maintain that a thorough case assessment is a good way to identify questions.
Finally, and most importantly, I hope this has been an opportunity to direct the attention to William’s case that it, and he, deserves. DCC is a great resource for that, as Alice constantly reminds us, the best way to solve cold cases is to continue discussing them, so let’s keep doing that shall we.
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Sue Carney is a UK-based consultant forensic scientist and expert witness, specialising in DNA and biological evidence.
Her career spans more than 20 years, including 10 years at the former UK Forensic Science Service and 8 years teaching forensic science at the University of Central Lancashire.
Since 2011, she has run Ethos Forensics, and continues to provide independent forensic science consultancy, mainly instructed by the defence in criminal casework. Sue was awarded Chartered Forensic Practitioner (Biology) status by the Chartered Society of Forensic Sciences in 2019.
In 2021, she commenced research towards her PhD in forensic science and law at Northumbria University.
You can find her on Twitter as @EthosForensics, where she mainly discusses science-related matters, and @LilacLounge, where she chats with friends, shares pictures of her dogs, and complains about the government.