Objective evaluation of similarity scores derived by Evofinder® system for marks on bullets fired from Chinese Norinco QSZ-92 pistols.

In recent years, many studies have been conducted in the field of firearm identification with the objective of providing an objective method of evaluating the comparison of cartridge cases. However, less attention has been paid to the objective evaluation of bullet comparisons. In this study, 1 000 registered Chinese Norinco QSZ-92 pistols were used, and a database of 2 996 bullets was constructed. Both the receiver operating characteristic (ROC) curve and the score-based likelihood ratio method were used to objectively evaluate the similarity scores derived by the Evofinder® system. The results indicate that this system has excellent ability to discriminate between the selected pistols. This paper proposes an objective evaluation method, which serves as a response to the ongoing debates regarding the foundation of the discipline.

Reproducibility and persistence of individual marks on 3000 fired bullets from five Chinese Norinco QSZ-92 9 × 19 mm pistols, and the search performance of Evofinder® to a 1000 firearm database of the same model firearm.

For firearm identification, foundational validity based on the reproducibility and persistence of characteristic marks must be established. We investigate the fired bullets of five Chinese Norinco QSZ-92 9 × 19 mm pistols over 3000 shots. The first 50 fired bullets are recovered, whereas every 50th fired bullet is recovered from the 51st to 3000th round. As such, 109 bullets are available for each pistol, and totally 545 bullets are introduced into the Evofinder® system. A large background database comprising 3000 bullets fired from 1000 registered QSZ92 9 × 19 mm pistols is used as interference. Both on-screen analysis and automatic comparison are performed. The first fired bullets from the five pistols are separately correlated with the database. The results show that although the similarity for known match bullets changes slightly as the shot number increases, the land-engraved area (LEA), groove-engraved area (GEA), and slippage marks can be reproducibly transferred to the fired bullets in consecutive shots. The Evofinder system ranks all known match bullets on the top of the correlation result with the combination of LEA, GEA, and slippage marks.

Sharing ballistic data across Europe: A prototype network between France and Switzerland using Evofinder®.

Today, there is a real political urge to see the sharing of ballistic data intensify across Europe mostly due to recent events such as terrorist attacks. However, technical constraints remain and two main options are being discussed. The first one relies on a centralized common database, implying a vendor monopoly for all Europe and a unified protocol among member states. The second one advocates for a distributed framework relying on existing national infrastructures and leaving each country responsible for its own protocols. This article describes a prototype network linking Switzerland and France using the Evofinder® system by ScannBI. We will first focus on how this network was set up, and then report some results from tests conducted to assess the viability of the concept. These results demonstrate that the second option cannot be discarded and pave the way for a distributed network. This solution appears to be cheaper, more adaptable and answers the practical needs of member states.

Performance Evaluation of a Registered Ballistic Database Using the Evofinder® System.

Firearms for police in China are registered along with their fired bullets and cartridge cases. A Registered Ballistic Database (RBD) of 1000 Norinco QSZ-92 pistols with registered ammunition was established and was evaluated through the Evofinder® system. In this research, 1000 bullets and 1000 cartridge cases were randomly selected and correlated against an RBD of 2996 bullets and 2999 cartridge cases. Examiners found that successful identifications all ranked 1st, supported with land (100%), groove (97%) engraved areas, and primary marks (85.6%) for bullets, and firing pin impressions (99.8%), and breech face marks (99.9%) for cartridge cases. Two known matches (KM) for the same pistol rank in the top two (100%). The distribution of similarity scores varies from marks; however, the Evofinder® system could still effectively distinguish known matches from known nonmatches (KNM) for either bullets or cartridge cases. This study demonstrates the efficiency of the RBD.

Individuality testing of new Glock pistol barrels "Marksman Barrel".

The Glock company's newest generation of pistols (G42/43, Gen5) is equipped with so-called "Glock Marksman Barrels" (GMB). These barrels feature an enhanced polygonal profile with right-hand twist and a small rifled profile on either side of the main polygonal field impression (Hernandez et al., 2016). Up until now, using the usual methods of comparison (automatic ballistic identification systems, ABIS and comparison microscope) it was difficult to assign bullets fired from a polygonal barrel to their origin with a high evidentiary value (Murdock et al., 1990) [5] (Northcutt, 2010). In this study, test shots from 18 Glock Gen5 pistols (9 Glock 17 pistols and 9 Glock 19 pistols) were compared to examine their differentiability. In addition, a Gen5 Glock 17 pistol was used to shoot 500 cartridges to determine to what degree the first projectile could be matched with the 500th (Zhang and Luo, 2018) [10]. This study was able to demonstrate that the new "Glock Marksman Barrel" (GMB) leaves marks of sufficient quality on projectiles to make high evidentiary value assignments of those projectiles to an individual firearm, both by using the comparison microscope as well as with an ABIS (Evofinder®). Further, it was possible to assign the cartridge casings to an individual pristine firearm.

Slight variations of breech face marks and firing pin impressions over 3070 consecutive firings evaluated by Evofinder®.

To investigate if and how the breech face mark and firing pin impression change over repeated firings, we used an automated ballistic identification system Evofinder® to study cartridge cases fired from five Chinese Norinco QSZ-92 9×19mm pistols. Each pistol fired 3070 consecutive shots. The first 20 cartridge cases were all introduced into the system. From the 21st until the 3070th shot, every ten cartridge cases were collected and one random sample of each group was introduced as the 30th, 40th, …, 3070th round. Thus, we introduced 325 specimens for each pistol and established a database of 1625 specimens. We used the first and every 100th specimen of each firearm to start correlations in the database and analyzed the results, especially the results of specimen 0001, 1000, 2000, 3000. Consequently, specimens fired closer in sequence to the specimen under examination had higher similarity scores. In boxplots, the boxes of known match specimens were much higher than boxes of known non match specimens. The Evofinder® ranked nearly all known match specimens in the first position of either firing pin impression list or breech face mark list. In conclusion, the two marks changed over 3070 consecutive shots and cartridge cases of nearer shot numbers were more similar. However, the variations of marks from the same firearm have not exceeded the differences between marks of different firearms and have not hindered the Evofinder® to make nearly 100% correct correlations.

Reproducibility of characteristic marks on fired cartridge cases from five Chinese Norinco QSZ-92 9×19mm pistols.

Reproducibility of characteristic marks on fired cartridge cases from five Chinese Norinco QSZ-92 9×19mm pistols over the course of 3070 shots is addressed using an Evofinder® system. The first 20 cartridges are all studied, while one random sample out of every ten consecutively fired cartridge cases is studied for the rest 3050 rounds. As such, a total of 325 cartridges are entered into the system for each pistol and a database consisting of 1625 cartridges from five pistols is established in this paper. Both onscreen examination and automatic correlation are used to examine the reproducibility. In the onscreen examination process, it is possible for firearm examiners to positively identify the first cartridge to the 500th, 1000th, 1500th, 2000th, 2500th, 3000th, 3070th cartridge. In the automatic correlation process, the first cartridge of each firearm is separately performed correlation against the database. It is found that the similarity score for match objects changes slightly as the shot number increases, indicating slight variations of marks. However, these variations have not prohibited the Evofinder® system to make correct correlation and rank 100% of the known match objects on the top of the correlation list by either firing pin impression or breech face mark. Thus, the reproducibility is proved statistically and objectively in this paper.

The reference ballistic imaging database revisited.

A reference ballistic image database (RBID) contains images of cartridge cases fired in firearms that are in circulation: a ballistic fingerprint database. The performance of an RBID was investigated a decade ago by De Kinder et al. using IBIS(®) Heritage™ technology. The results of that study were published in this journal, issue 214. Since then, technologies have evolved quite significantly and novel apparatus have become available on the market. The current research article investigates the efficiency of another automated ballistic imaging system, Evofinder(®) using the same database as used by De Kinder et al. The results demonstrate a significant increase in correlation efficiency: 38% of all matches were on first position of the Evofinder correlation list in comparison to IBIS(®) Heritage™ where only 19% were on the first position. Average correlation times are comparable to the IBIS(®) Heritage™ system. While Evofinder(®) demonstrates specific improvement for mutually correlating different ammunition brands, ammunition dependence of the markings is still strongly influencing the correlation result because the markings may vary considerably. As a consequence a great deal of potential hits (36%) was still far down in the correlation lists (positions 31 and lower). The large database was used to examine the probability of finding a match as a function of correlation list verification. As an example, the RBID study on Evofinder(®) demonstrates that to find at least 90% of all potential matches, at least 43% of the items in the database need to be compared on screen and this for breech face markings and firing pin impression separately. These results, although a clear improvement to the original RBID study, indicate that the implementation of such a database should still not be considered nowadays.