Reevaluation of Forensic Practices in the
Somerton Man Case Identification
Introduction
In 2022, a claim was made that a man known as Carl Webb was the Somerton Man. The claim was, based on DNA analysis of a single 50-mm rootless hair shaft. The claim has ignited public interest for some time and sparked important questions regarding the processes that were employed in the analysis and conclusions that were drawn.
This post examines some of the complexities and challenges surrounding the DNA extraction and identification process, including the impact of mortuary practices, environmental exposure, and the presence of metals within the hair shaft. With even earlier findings, including spectrometric analysis showing lead and copper incorporation within the hair shaft close to the time of death, a clearer understanding of the case’s scientific challenges has emerged.
These elements highlight critical considerations in the handling of forensic evidence and the importance of transparency in the interpretation of historical DNA samples. Numerous citations are included here with many more available for the researcher.
1. Mortuary Practices and the Creation of the Plaster Bust
Human Hair as a Reinforcing Agent and Lime Putty in Plaster Casts: Historically, animal hair was often added to lime-based plaster for added strength, human hair was sometimes used due to its availability. When lime putty is added, it not only strengthens the plaster but can also accelerate organic degradation, posing a risk to any biological samples preserved in such a medium. This adds complexity to the identification process, as no precedents exist for successful DNA extraction from lime-based plaster casts. Consequently, the potential for DNA preservation in the Somerton Man’s bust is inherently limited. The use of human hair in the plaster bust has yet to be confirmed, it is suggested that an examination of other plaster casts made by the late Mr. Paul Lawson during his tenure at the SA Museum, might reveal the practices that he employed.
Cornish LimeLimebase
.Use of Mortuary Soap Containing Sodium Hypochlorite: Paul Lawson, the technician who created the bust, used mortuary soap containing sodium hypochlorite to slick down the Somerton Man’s hair. Sodium hypochlorite, a strong oxidizing agent, may degrade or alter DNA if it comes into direct contact with biological material, especially over time. This practice may explain the presence of sodium in the mass spectrometry analysis and could have chemically impacted any DNA within the hair. Denaturation
Release Agents Used on the Skin: Lawson applied a release agent to the face, neck, and shoulders to facilitate mold removal. Release agents, while useful for casting, can introduce additional chemicals to the skin and hair, potentially affecting sample integrity and complicating the interpretation of any surface DNA. Mold Release Agents
2. Embalming Process, Preservation, and Environmental Exposure
Extended Embalming Process: Undertaker Laurie Elliot conducted a thorough embalming process over approximately three months, from December 1948 to March 1949, using formaldehyde and other preservation chemicals. Formaldehyde, known to cause DNA cross-linking and degradation, likely compromised the DNA in any samples taken from the body, including hair samples. This extensive exposure introduces another layer of complexity in attempting to extract usable genetic information. Formaldehyde Embalming
Freezing and Thawing Cycles: During the preservation period, the Somerton Man’s body underwent repeated freezing and thawing. These cycles create cellular stress and molecular degradation, which likely impacted DNA quality. Such conditions further exacerbate the challenges associated with extracting viable genetic material from historical samples. Freeze-Thaw cycles
Environmental Exposure and Metal Incorporation within the Hair Shaft: A mass spectrometry analysis performed on hair samples extracted from the plaster bust showed lead and copper within the hair shaft, and it was suggested that these metals were incorporated during the final two weeks of the Somerton Man’s life. Metals like lead and copper are generally absorbed internally through environmental exposure rather than through external contamination, indicating a likely occupational or environmental source of exposure. This finding points to significant recent environmental interactions, rather than post-mortem contamination, and offers potential insight into the man’s life shortly before his death.
Sodium Presence: The analysis also detected sodium, likely attributed to the sodium hypochlorite in the mortuary soap Lawson applied. This substance was intended to manage the hair during the bust-making process but may have contributed to the presence of sodium ions detected in the spectrometry results.
3. Lack of Documentation and Chain of Custody in DNA Sample Collection
Unclear Origins of the 50-mm Rootless Hair Shaft: At the heart of the DNA identification claim is a 50-mm rootless hair shaft; however, no documentation exists specifying who found this sample, when it was located, how it was extracted, or how it was stored. This absence of a documented chain of custody raises serious questions regarding the sample's authenticity and handling. Without clear records, it is difficult to verify the sample’s integrity, which is crucial in high-profile forensic cases. To the date of this post,the IEEE Spectrum Article which goes into detail on the processes made no mention of where, when,. how and by whom the 50mm sample was found and extracted. !EEE Spectrum Article
Dr. Xanthe Mallet’s Concerns on DNA Protocol Adherence: Dr. Xanthe Mallet, an experienced criminologist, raised concerns about adherence to standard DNA protocols in the case. She emphasized the need for rigorous forensic practices, particularly in handling degraded samples with historical significance. Her insights highlight the risks inherent in cases where documentation and protocol adherence may be compromised, further underscoring the importance of transparent practices in forensic identification. ABC TV VIDEO
4. Analytical and Procedural Limitations in DNA Testing
Imputation in Genetic Analysis: Due to the compromised nature of the DNA sample, imputation was used to infer missing genetic data. While useful in research contexts, imputation introduces a level of uncertainty in forensic applications, particularly with degraded samples. The potential for inaccuracy in the imputed data raises concerns about the reliability of the genetic connections linking the Somerton Man to Carl Webb. The Imputation Process In DNA Analysis
Absence of Confirmatory Testing: Given the lack of a documented chain of custody and reliance on imputation, additional independent verification of the DNA findings would strengthen the claim. Without confirmatory testing, it is challenging to substantiate the identification with confidence. Confirmatory testing of DNA samples
5. Summary of Methodological Concerns and Implications
Lack of Documented Sample Provenance: The absence of clear records for the discovery, extraction, and preservation of the hair shaft sample introduces significant uncertainty.
Chemical Contamination Risks: Embalming chemicals, mortuary soap, release agents, and lime-based plaster compounds may have affected DNA integrity, adding layers of complexity to the analysis.
Environmental Exposure Evidence: The detection of lead and copper within the hair shaft suggests occupational or environmental exposure shortly before death, providing potential insights into the Somerton Man’s final days. The numerous known occasions when thawing and refreezing would have occurred could have negatively affected the DNA samples.
Expert Concerns on Forensic Standards: The comments by Dr. Xanthe Mallet emphasize the importance of adherence to DNA extraction and analysis protocols, particularly in cases involving degraded historical samples.
Conclusion
In my view and for the reasons outlined in this post, the identification of Carl Webb as the Somerton Man remains speculative given the uncertainties surrounding the DNA sample, mortuary practices, environmental exposures, and methodological limitations. The mass spectrometry analysis revealing metals within the hair shaft suggests significant pre-mortem environmental exposure, adding complexity to the forensic narrative. Furthermore, the absence of documented protocols in the discovery and handling of the 50-mm hair shaft highlights the need for transparency in forensic processes. In high-profile historical cases, establishing a clear chain of custody and conducting independent verification are essential for supporting robust and credible forensic conclusions. This case underscores the importance of methodological rigor, transparency, and adherence to forensic standards in advancing public trust and scientific integrity.