Benefits, Risks, and Myths of TASER® Handheld Electrical Weapons

Homicide Manner-of-Death Classification in Arrest-Related Death

ABSTRACT

Multiple studies have documented various factors that influence or determine forensic pathologist classification of manner of death. There do not appear to be any published studies on manner of death classification specifically regarding arrest-related deaths (ARDs). The goal of this study was to consider a large body of cases of nonfirearm ARDs to analyze the homicide classification with regards to numerous decedent and practitioner (medical examiner/coroner [ME/C]) variables. We analyzed 1145 US autopsy reports from the years 2006-2020, inclusive, and considered decedent variables of age, ethnicity, height, weight, body mass index, toxicology, and mention of a conducted electrical weapon and ME/C influence variables of gender, country region, and year. We found that the homicide classification likelihood increased by a factor of 1.04-1.05 per year, 1.34-1.37 for a female medical examiner, and 1.4-1.5 going from Southern states to Western states. There is an increasing trend for ME/C to label nonfirearm ARDs as homicides in the United States. The homicide classification is more common in Western states and less common in Southern states, and it was more common with a female ME/C.

TASER CEW distance determination for models X26P, X2, and TASER 7

TASER weapons, classified as Conducted Energy Weapons (CEWs) are used by law enforcement as electrical, non-lethal weapons. A CEW's long distance method of deployment launches two barbed probes that embed into the target, before electricity is cycled from one probe to the other. The resulting muscle contractions help incapacitate the intended target. Currently, there is no research on the accuracy of variability of CEW probe spread in determining the distance of the shooter. Thus, in this study, a method of distance determination for TASER models X26P, X2, and TASER 7 was established to help estimate the relative locations of individuals during crime scene reconstruction. Each of four probe cartridge types were launched for six repetitions towards vertical cardboard targets from three different distances (n = 72). The probe spread on the targets was measured for each cartridge and plotted against CEW-To-Target (CTT) distance. Linear regression trendlines and standard deviations were generated for each cartridge type. Results demonstrated probe spread distances to be proportional to probe launch angles, and greater CTT distances resulted in greater standard deviation. Standard error of the estimate was calculated for all four linear regression equations and their ability to predict CTT distance when given probe spread measurements. The mean standard error values appeared acceptable for the X2 (0.460 m), TASER 7 CQ (0.273 m), and X26P (0.322 m) CEW models, while the mean error calculated for the TASER 7 Standoff model (0.846 m) was considerably greater. We expect our findings will help establish a reliable method of distance determination for CEWs, and perhaps with a larger sample size, more thoroughly examine the accuracy of the linear regression equations. CEW distance determination has the potential to provide support in contextualizing crime scene reconstruction with further research. By providing distance estimations alongside a standardized guide of error allowance, it would be possible to induce how far apart individuals were at the time a CEW was fired, within the calculated window of deviation, and in a statistical degree of confidence.

Confusion between firearms and electrical weapons as a factor in police shootings

Conducted electrical weapons (CEW) have risks including trauma associated with uncontrolled falls, probes penetrating the eye, and fume ignition. A lesser-known risk is weapon-confusion error with officers mistakenly discharging their firearm when they intended to deploy their electrical weapon. We searched for incidents of possible weapon confusion with the TASER® brand CEWs via open-source media, litigation filings, and a survey of CEW law enforcement master instructors. We found 19 incidents of possible CEW weapon confusion in law enforcement field uses from January 2001 to April 2021. We eliminated a case as not meeting our criteria for probable weapons confusion leaving 18 cases, thus giving a demonstrated CEW discharge risk of 3.9 per million with confidence limits (2.4-6.2 per million) by Wilson score interval. Ipsilateral carry of the weapons was historically correlated with increased risk vs. contralateral carry. Officer gender was not a predictor of weapon confusion. The psychological issues behind weapon confusion under stress are discussed. The concurrent carry of electrical weapons and firearms presents a very small but real risk of injury and death from confusion between an electrical weapon and a firearm.

Elektroschockdistanzwaffen Taser® X2 und T7

Die medizinische Beurteilung von Verletzungen und potenzieller todesursächlicher Relevanz einer Stromexposition durch eine Elektroschockdistanzwaffe beschränkt sich nicht allein auf die situativen Gegebenheiten und die morphologische Befunderhebung, sondern beinhaltet auch eine intensive Analyse polizeilicher Ermittlungen und die Auswertung von Zeugenaussagen sowie vorangegangener medizinischer Maßnahmen. Insbesondere bei zeitlich relevanter Nähe zwischen Exposition und Todeseintritt muss die Wirkung der übertragenen Stromimpulse in Zusammenhang mit der meist komplexen Einsatzsituation und der medizinischen Vorgeschichte des Geschädigten beurteilt werden. Ein detailliertes Wissen über die konkrete und auch abstrakte Wirkungsweise, Wirksamkeit und Risiken von Elektroschockdistanzwaffen ist hierfür unabdingbar.

Output of Electronic Muscle Stimulators: Physical Therapy and Police Models Compared

INTRODUCTION

Both physical therapists and police officers use electrical muscle stimulation. The typical physical therapist unit is attached with adhesive patches while the police models use needle-based electrodes to penetrate clothing. There have been very few papers describing the outputs of these physical therapy EMS (electrical muscle stimulator) units.

METHODS

We purchased 6 TENS/EMS units at retail and tested them with loads of 500 Ω, 2 kΩ, and 10 kΩ.

RESULTS

For the typical impedance of 500 Ω, the EMS units delivered the most current followed by the electrical weapons; TENS units delivered the least current. At higher im-pedances (> 2 kΩ) the electrical weapons delivered more current than the EMS units, which is explained by the higher voltage-compliance of their circuits. Some multi channel EMS units deliver more calculated muscle stimula tion than the multi-channel weapons.

CONCLUSION

Present therapeutic electrical muscle stimula-tors can deliver more current than present law-enforcement muscle stimulators.

Detection of Arcing and High Impedance with Electrical Weapons

INTRODUCTION

Conducted electrical weapons are primarily designed to stop subjects from endangering themselves or others by deploying 2, or more, probes to conduct current via the body to induce motor-nerve mediated muscle contractions, but probe impedance can vary significantly including open circuits from probes failing to complete or maintain a circuit.

METHODS

We tested 10 units of the TASER^® 7 model with a range of impedances and open circuit conditions. Pulse data (stored in the device's memory) were used to predict the load resistances and detect arcing conditions. Acoustical data (recorded externally) was evaluated on an exploratory basis as a secondary goal.

RESULTS

The average error of predicted resistance, over the physiological load range of 400-1000 Ω, was 8%. Arcing conditions was predicted with an accuracy of 97%. An arcing condition increases the duration of the sound generation.

CONCLUSIONS

The TASER 7 electronic control device stored pulse-log data for charge and arc voltage yielded forensic analysis of the load resistance with reliable accuracy.

Estimation of Physiological Impedance from Neuromuscular Pulse Data

INTRODUCTION

A Conducted Electrical Weapon (CEW) deploys 2, or more, probes to conduct current via the body to induce motor-nerve mediated muscle contractions, but the inter-probe resistances can vary and this can affect charge delivery. For this reason, newer generation CEWs such as the TASER^® X3, X2 and X26P models have feed-forward control circuits to keep the delivered charge constant regardless of impedance. Our main goal was to explore the load limits for this "charge metering" system. A secondary goal was to evaluate the reliability of the "Pulse Log" stored data to estimate the load resistance.

METHODS

We tested 10 units each of the X2 (double shot), X26P, and X26P+ (single-shot) CEW models. We used non-inductive high-voltage resistor assemblies of 50, 200, 400, 600, 1k, 2.5k, 3.5k, 5k, and 10k Ω, a shorted output (nominal 0 Ω), and arcing open-circuits. The Pulse Log data were downloaded to provide the charge value and stimulation and arc voltages for each of the pulses in a 5 s standard discharge cycle.

RESULTS

The average reported raw charge was 65.4 ± 0.2 µC for load resistances < 1 kΩ consistent with specifications for the operation of the feed-forward design. At load resistances ≥ 1 kΩ, the raw charge decreased with increasing load values. Analyses of the Pulse Logs, using a 2-piece multiple regression model, were used to predict all resistances. For the resistance range of 0 - 1 kΩ the average error was 53 Ω; for 1 kΩ - 10 kΩ it was 16%. Muzzle arcing can be detected with a model combining parameter variability and arcing voltage.

CONCLUSIONS

The X2, X26P, and X26P+ electrical weapons deliver an average charge of 65 µC with a load resistance < 1 kΩ. For loads ≥ 1 kΩ, the metered charge decreased with increasing loads. The stored pulse-log data for the delivered charge and arc voltage allowed for methodologically-reliable forensic analysis of the load resistance with useful accuracy.

Police shootings after electrical weapon seizure: homicide or suicide-by-cop

PURPOSE

Risks of handheld electrical weapons include head impact trauma associated with uncontrolled falls, ocular probe penetration injuries, thermal injuries from the ignition of volatile fumes, and weapon confusion police-involved shooting. There is also an uncommon but critical risk of a shooting after a subject gained control of an officer's electrical weapons.

METHODS

The authors searched for police shooting incidents involving loss of control of TASER® weapons via open-source media reports, crowd-sourced internet sites, litigation filings, and a survey of Axon law-enforcement master instructors.

RESULTS

The authors report 131 incidents of subjects attempting to or gaining control of an officer's electrical weapon from 2004 to 2020, 53 of which resulting in a shooting. These incidents demonstrated a risk of 11.8 shootings per million electrical weapon discharges (95% confidence limits of 9.0 to 15.1 per million by Wilson score interval).

CONCLUSIONS

The use of electrical weapons presents a rare but real risk of injury and death from a shooting following a subject's attempts to gain control of the weapon.

Aspiration-related pneumonia after Taser exposure - A multiple causations mechanism

Arrest-related deaths in the context of Conducted Electrical Weapon (CEW) deployment are rare. The evaluation of such complex events is a challenge for the forensic scientist. We present a case of a 49-year old man, who was exposed to a Taser X26P during a confrontation with the police. He lost consciousness, vomited, aspirated and died after having been hospitalized for several days at the ICU. Based on the patient´s medical history, autopsy findings, witness testimonies, and reliable clinical and toxicological blood parameters, the most probable cause and mechanisms of his death are discussed. The present work demonstrates, based on one case report, the possibilities as well as limitations of forensic assessment in CEW-related deaths.

Electrical weapons and rhabdomyolysis

It has been suggested that an application of a conducted electrical weapon (CEW) might cause muscle injury such as rhabdomyolysis and an acute inflammatory response. We explored this hypothesis by testing the effects of electrical weapons on circulating markers of inflammation and muscle damage. In a prospective study, 29 volunteers received a full-trunk 5-s TASER® X26(E) CEW exposure. Venous blood samples were taken before, 5 min after, and at 24 h following the discharge. We tested for changes in serum levels of C-reactive protein (CRP), alkaline phosphatase (ALP), myoglobin, albumin, globulin, albumin/globulin ratio, aspartate and alanine aminotransferase, creatine kinase, total protein, bilirubin, and lactic acid dehydrogenase. Uncorrected CRP and myoglobin levels were lower in the immediate post exposure period (CRP levels 1.44 ± 1.39 v 1.43 ± 1.32 mg/L; p = 0.046 and myoglobin 36.8 ± 11.9 v 36.1 ± 13.9 μg/L; p = 0.0019) but these changes were not significant after correction for multiple comparisons. There were no changes in other biomarkers. At 24 h, CRP levels had decreased by 30% to 1.01 ± 0.80 mg/L (p = 0.001 from baseline). ALP was unchanged immediately after the CEW application but was reduced by 5% from baseline (66.2 ± 16.1 to 62.7 ± 16.1 IU/L; p = 0.0003) at 24 h. No other biomarkers were different from baseline at 24 h. A full-trunk electrical weapon exposure did not lead to clinically significant changes in the acute phase protein levels or changes in measures of muscle cellular injury. We found no biomarker evidence of rhabdomyolysis.

Electrical weapons, hematocytes, and ischemic cardiovascular accidents

BACKGROUND

There have been case reports following the use of a conducted electrical weapon (CEW) suggesting that these devices might affect coagulation or thrombosis in at-risk individuals. The aim of this manuscript therefore is firstly to explore this hypothesis by reviewing each of these cases and secondly to report the results of a prospective study exploring a priori the effects of electrical weapons on hematocytes in a group of human volunteers.

METHODS

First, we systematically reviewed all cases of adverse outcomes following CEW discharge that could be due to an effect on coagulation or thrombosis, with particular focus on the clinical scenario and its relationship with the weapon discharge. Second, we assessed hematocyte levels in venous blood from 29 volunteers before, 5 min after, and 24 h after receiving a full-trunk 5-s TASER® X26(E) CEW exposure.

RESULTS

Following extensive review of the literature, we found 3 relevant case reports of possible vascular thromboembolic clinical events after CEW exposure, specifically a case of ischemic stroke, and 2 cases of ST-segment elevation myocardial infarctions. Review of these published cases failed to establish a plausible linkage to the CEW beyond a temporal association with significant emotional and physiological stress from a violent struggle. Our prospective study of biomarker change following CEW discharge revealed acutely increased values for WBC (white blood cells), specifically lymphocytes and monocytes, and a raised platelet count. Neutrophil levels decreased as a percentage of WBC. While these changes were statistically significant at 5 min, all results remained within established reference ranges. At 24 h, all values had returned to baseline except total WBC which decreased to slightly below baseline but was still within the normal reference range.

CONCLUSIONS

A review of clinical cases, of ischemic or thrombotic events revealed no direct association with the CEW discharge. A full-trunk electrical weapon exposure did not lead to hematocyte changes beyond normal clinically expected variations in similar acute response scenarios. The case report and biomarker data do not support the hypothesis that a CEW discharge is associated with changes likely to promote coagulation or thrombus formation.