Quantitative characterisation of ballistic cartridge cases from micro-CT

The use of micro-CT in the investigation of a case involving 3D printed firearms

This paper highlights how micro-CT was used to assist in the investigation of hybrid firearms constructed using a mixture of plastic and metal components, as a complementary technique to the physical examination performed by firearms experts. In recent years, there has been an increase in the complexity and sophistication of 3D printed and hybrid firearm designs. This was also the case in the investigation presented herein, with the firearms seized demonstrating a step change in the threat level they pose through their complexity. Thus, we describe how data produced from micro-CT scans was used to help firearms experts study the viability and mechanics of two hybrid weapons prior to dismantling and test-firing. This process aided experts in determining whether components were 3D printed or manufactured through other means, whilst ensuring that a digital record (digital twin) was retained in case evidence was damaged during testing. Finally, we show how the data was presented visually through animations and as evidence in court. This proved to be imperative when communicating to the judge, jury, and wider investigating teams, the complex multiple components and mechanisms within the firearms.

Forensic applications of micro-computed tomography: a systematic review

Purpose

The aim of this systematic review was to provide a comprehensive overview of micro-CT current applications in forensic pathology, anthropology, odontology, and neonatology.

Methods

A bibliographic research on the electronic databases Pubmed and Scopus was conducted in the time frame 01/01/2001–31/12/2021 without any language restrictions and applying the following free-text search strategy: “(micro-computed tomography OR micro-CT) AND (forensic OR legal)”. The following inclusion criteria were used: (A) English language; (B) Application of micro-CT to biological and/or non-biological materials to address at least one forensic issue (e.g., age estimation, identification of post-mortem interval). The papers selected by three independent investigators have been then classified according to the investigated materials.

Results

The bibliographic search provided 651 records, duplicates excluded. After screening for title and/or abstracts, according to criteria A and B, 157 full-text papers were evaluated for eligibility. Ninety-three papers, mostly (64) published between 2017 and 2021, were included; considering that two papers investigated several materials, an overall amount of 99 classifiable items was counted when referring to the materials investigated. It emerged that bones and cartilages (54.55%), followed by teeth (13.13%), were the most frequently analyzed materials. Moreover, micro-CT allowed the collection of structural, qualitative and/or quantitative information also for soft tissues, fetuses, insects, and foreign materials.

Conclusion

Forensic applications of micro-CT progressively increased in the last 5 years with very promising results. According to this evidence, we might expect in the near future a shift of its use from research purposes to clinical forensic cases.

Advantages of micro-CT in the case of a complex dismemberment

This case study reports the advantages of micro‐CT to aid the investigative process in a complex dismemberment case. Micro‐CT was successfully implemented to scan all skeletal remains of a dismembered female. The digital models were utilized to (i) screen for any further injuries not related to the dismemberment, (ii) provide measurements from false starts non‐destructively, and (iii) visually represent the evidence in a structured format in court to improve the understanding of the forensic evidence by the jury. Acquiring high‐resolution scans in this manner improved the efficiency of the forensic investigation by screening the remains and provided complementary toolmark evidence to the investigating team and forensic pathologist. A total of 14 false starts were identified along with the directionality of each dismemberment cut. Furthermore, the visual 3D representation of the remains in court provided a powerful tool to communicate this important evidence to the jury and form a prosecution narrative. As a forensic radiological method, micro‐CT provided valuable information both in the investigation and the court presentation.