Diatoms and homicide
Introduction
We have recently assessed the validity and utility of the diatom test for drowning by analysing the outcome of the test in 771 cases of drowning [1]. We found that the presence of diatom frustules in bone marrow can be used to diagnose drowning in approximately one-third of freshwater drownings. There was a high incidence of positive test outcomes in months of peak freshwater concentration of diatoms. In an analysis of cases of drowning in which a sample of drowning medium was available for examination, we found that the same types of diatoms could be found in 90% of cases indicating that the diatoms originated from the drowning medium [2]. Taken together these data support the utility and validity of the diatom test for determining cause of death when drowning is suspected on the basis of autopsy findings or circumstances surrounding death.
In this report, we describe six illustrative cases of homicidal drowning (Table 1) in which the application of the diatom test implicated drowning as a cause of death. In many of these cases, the circumstances and postmortem findings did not initially suggest drowning as a cause of death. These cases underscore the utility of the diatom test in suspicious deaths or homicides in which conventional investigations do not led to determination of a definitive cause of death. In addition, the cases show that the correlation of the type of diatoms recovered from tissues and putative sites of drowning may help to localize a site of drowning.
Section snippets
Material and methods
In all cases, bone marrow from one or both femurs were used for the extraction of diatoms utilizing a method described previously 1, 3. Briefly, femurs were sawed along the long axis, the bone marrow (∼50 g) removed using a clean spatula and placed into a boiling flask. Approximately 50 ml of concentrated analytical grade nitric acid was added and the marrow-acid suspension was simmered on a hot plate for approximately 48 h in a fume hood. The suspension was then cooled to room temperature and
Case 1
The body of a 56 year old woman was found face down floating in a river. At autopsy, there was recent haemorrhage into the right sternomastoid muscle with fracture of the right greater cornu of the hyoid bone with local haemorrhage and recent bruising involving the tip of the tongue. There was bilateral pulmonary oedema (right lung 450 g, left lung 400 g) and 300 ml of watery fluid in the stomach. Death was attributed to the combined asphyxial effects of strangulation and drowning.
A nitric acid
Discussion
The reported cases illustrate the utility of the diatom test in the medicolegal investigation of homicidal drowning Table 1. The main points illustrated by the case reports are that: (i) the diatom test for drowning can implicate drowning as a cause of death even when the autopsy and circumstances do not suggest drowning; and (ii) drowning is further substantiated when the type of diatom in the bone marrow matches diatoms present in the putative drowning medium.
In most of the reported cases,
Acknowledgements
Some of the cases were processed under the direction of the late Dr. John Hillsdon-Smith, former Director of Forensic Pathology for the Province of Ontario. The investigating officer who collected the water sample for case three was Supt. William C. Bowles. The author thanks Vera Mont and Jurek Ladziak for preparation of acid digests.
References (3)
- et al.
The diagnostic value of the diatom test for drowning. I. Utility: a retrospective analysis of 771 cases of drowning in Ontario, Canada
J. Forensic Sci.
(1997)
Cited by (59)
Potential of photoautotrophic microbial organisms in deciphering forensic issues
2023, Legal MedicineThe body recovered from water: considerations for an approach to the non-suspicious post-mortem examination
2021, Diagnostic HistopathologyDiatoms: A novel cause of granulomatous inflammation of the head and neck
2021, Oral Surgery, Oral Medicine, Oral Pathology and Oral RadiologyTransferability of Australian diatoms to clothing: Assessment of several extraction methods on different fabric types under laboratory conditions
2020, Forensic Science InternationalCitation Excerpt :This idea stems from the forensic dogma “every contact leaves a trace” – known as Locard's exchange principle [11] – and in the field of forensic geoscience [12]. In this context, forensic geoscience refers to the possibility of using trace evidence such as soil, sediment and microscopic algae (diatoms especially), to support the diagnosis of death by drowning [13,14] and to verify that contact occurred between a suspect and a specific water body [8,15]. Diatoms are photosynthesizing unicellular microalgae that have a siliceous skeleton (frustule made of two overlapping valves) with specie-specific morphological features.
The transfer of diatoms from freshwater to footwear materials: An experimental study assessing transfer, persistence, and extraction methods for forensic reconstruction
2017, Science and JusticeCitation Excerpt :Simultaneously, recent years have also seen a growing interest in environmental forms of trace evidence; the use of mineral grains [16–18], palynomorphs [19–21], bryophyte shoots [22,23], and algae [24,25] to exclude (or fail to exclude) contact between suspects, victims, objects, and crime scenes within forensic scenarios. One form of evidence that has proved particularly useful within aquatic environments is diatoms; unicellular algae that have traditionally found forensic application within the field of pathology [25–28]. Composed of two silica valves linked by a girdle element, the diatom frustule can be well-preserved within sediments and forensic contexts [25].