POLICING FORENSIC EVIDENCE

If there had been no video of Derek Chauvin killing George Floyd on May 25, 2020, the legal and public response might have quite different. Before a series videos captured by witnesses security cameras surfaced, Minneapolis Police Department issued statement: “After got out his car, he physically resisted officers. Officers were able to get suspect into handcuffs noted appeared be suffering medical distress.”1 The Chief Medical Examiner for county did determine that Floyd’s death was homicide but also speculated suffered from “significant conditions,” such as drug use heart condition, may increased likelihood death.2 At Chauvin’s trial, examiner testified, “In my opinion, law enforcement subdual, restraint, neck compression just more than Mr. could take virtue those conditions.”3 Attorneys family commissioned an independent autopsy found contributing factors.4 More specifically, they cause not attack rather “mechanical asphyxia”—meaning flow oxygen cut off so Floyd, told officers, simply breathe.5 As Martin Tobin testified at criminal given force placed neck, “[a] healthy person subjected what would died.”6It aberration examiner’s determinations regarding hotly disputed. There is long, troubling history prosecution, in media releases, labeling people killed police criminals or users persons with preexisting conditions.7 Forensic evidence, which examiners coroners set conclusions certificates, has played role providing faulty support claims.8 All too often, questionable findings shared our courts, including omitting entirely cases killings.9 coroner examination field rife poor methods. A landmark 2009 National Academy Sciences report (“NAS Report”) called investigations United States “fragmented” system “deficient” its practices replacement local coroners' offices system.10The case one high-profile example larger problem: evidence collection, when it conducted outside experts crime labs, lacks adequate scientific safeguards result prone bias error.11 central function policing gather during investigations. Law receives great deal deference carries investigative functions. While detailed constitutional procedure rules regulate traditional functions, searches seizures, very little regulation forensic any kind, much less informed community priorities, research, policy.12 To sure, growing number policies guidelines reflect recent effort emphasize accurate impartial collection. International Association Chiefs taken active promoting consideration ways improve “accuracy thoroughness” investigations.13 Far needed ensure accuracy thoroughness.A second forensics gone wrong illustrates problem, setting laboratory setting. Science (DFS) Washington, D.C., supposed model lab change work scene better. D.C. government passed Act 2011 make require accredited.14 It paid tens millions dollars large new facility.15 Unfortunately, while accredited labs way quality control typical agency, do controls present clinical lab.In murder Judge Todd Edelman ruled August 2019 after hearing several extensive hearing, concerned published studies show DFS reliably “source attribution.”16 judge held most expert say “the recovered firearm [could not] excluded source cartridge casing alleged shooting.”17 involving firearms analyzed 2017 charges against two men killings front Edelman.18 group reported same weapon fired cartridges shootings.19 Perhaps because skeptical past, prosecutors wanted sure; took unusual step asked look evidence.20 That sure clear different involved.21 defiantly insisted fact “administrative error” now deemed “inconclusive.”22The went damage mode. director “darn good lab.”23 Management American Standards Institute Accreditation Board, lab, made “inconclusive” finding initiating review incident. In April lab’s accreditation suspended.24 stopped doing result. Prosecutors opened probe unit disagreed eleven cases. scathing audit managers sought conceal problem before pressured others “inconclusive.”25 One recalled how tried “push back long could” wished resigned protest.26 auditors concluded this illustrated “very serious” problems management indicated lack adherence “core principles integrity” ethics. resigned. letter “potential concealment” errors fingerprint well.27 September 2021, disbanded unit. investigation pending, remains closed.28As these examples both show, has, varying degrees, left station manner represents highly incomplete much-needed transition sound science. years, can adhere standards. recommendation NAS Report, brought together leading scientists consider path forward science, centered independence methods.29 best, some obtained financial structural accountability should accompany embrace methods.Many are asking questions about define safety.30 Even area where greater expectation science will used service safety, police’s collecting testing remained unasked. untrained police, trained scientists, collect potentially alter contaminate scenes.31 Further, we allow oversight direct influence their work, never tolerated experiment, lab.32 deploy technologies, hopefully continue asked, scrutiny resulted old like pathology examinations comparisons, used. reason remain under-examined neither courts nor readily access procedures employ results obtain.However, movement bring standards forensics, increasingly embraced actors, potential address long-standing needs. I discuss essay, promise generally. We using broadly, evaluate fairness safety outcomes. focus here three specific core policing: (1) independence, (2) accuracy, (3) oversight.The Report warned “lack independence” objectivity harm justice.33 Traditionally, largely function, States. Early small operated departments, following early Federal Bureau Investigation (FBI) lab.34 By 1960s, every state run enforcement.35 Today, over four hundred publicly funded 14,300 employees.36 Very few enforcement.Nor done professionals necessarily enforcement. This begins scene. Such variety roles, officers working departments crime-lab analysts, technicians, others.37 Evidence collection priorities resources affect initial decision whether test evidence. Recent inquiries audits failed particularly untested rape kits. study forty percent unanalyzed estimated testable DNA.38 Los Angeles County, Human Rights Watch protests, sheriffs began years backlogs.39 serious non-testing, federal grant support,40 twenty-six states enacted statutes requiring inventories sexual assault evidence.41Police begin process examining often then affects lab.42 developing promote scene.43 Not only training adequately scene, fail probative.44 preemptively themselves inaccurate For example, commercial drug-testing kits carefully validated; issue shown high error rates. tests followed up rigorous test, meantime, arrested face pressure plead guilty. Harris Texas, District Attorney’s Office Conviction Integrity Unit uncovered hundreds Texas Commission later unreliable convictions subsequently reversed.45 2017, Houston ceased tests, widely other jurisdictions.In areas, concern. U.S. Supreme Court suggestive eyewitness identifications violate Due Process Clause. Court’s ruling Manson v. Brathwaite due so-called reliability factors assess procedures.46No inquiry exists body research documented cognitive biases work. Psychological techniques involve degree judgment interpretation, vulnerable bias.47 laboratory, rarely blind, range communications results. beginning submission analysts communicate hear task-irrelevant biasing information.In famous all five experienced reviewed prints course ordinary work.48 know Professor Itiel Dror colleagues each looked real-life source.49 Other separately agreed source. infamous Madrid bombing case, senior FBI mistakenly implicated innocent Portland, Oregon, lawyer.50 After having made, reached conclusion: persisted reporting came source, “definite non-match” prints, fourth “inconclusive.”51Addressing becoming part laboratories. Adoption procedural protections reduce bias. linear sequential approach developed comparative pattern disciplines. 2016 President’s Council Advisors Technology (PCAST) recommends comparisons: “should required complete document analysis latent looking known fingerprint” prevent circular reasoning forth between encourages disregard differences.52 protection information analysts.53 PCAST recommended additional data comparison evaluation.”54 Information if necessary drawing propositions question, method question. Separation roles help keep analysts.55 relationships hallmark functionally science.56 Those reforms slowly being implemented, however.A wide practitioners, lawmakers, lawyers, judges, forensics. emphasized “some disciplines supported systematic validate discipline’s basic premises techniques.” Slowly, begun conducted, learned methods go wrong.57The relatively piecemeal. Many follow based Daubert Merrell Dow Pharmaceuticals58 progeny, task judges gatekeeping responsibilities understood ineffectively Leading reports, influential lawyers effective reviewing cases.59 Constitutional bars failure disclose exculpatory outright fabrication fabricating knowingly perjured testimony violates Clause.60 addition, must supply “any favorable acting government’s behalf police.”61 No apart elemental disclosure non-fabrication rules.For decades, types certain conclusions.62 Harry T. Edwards put it, “The misled time told, I, comparisons involved essentially zero rate, without ever understanding that’s completely inaccurate.”63 Yet, tested assumptions relied upon decades. recently, Reports highlighted need objective method, you seeing produces results.64 However, subjective clearly defined steps. process: mind “black box” reaches judgments experience.65 examiner, give samples realistic difficulty correct answer advance.66 type proficiency routine performance examiners, except elementary designed rigorous.67 Entire fields lacked establish reliability. And, underscored, “without appropriate estimates statement similar—or even indistinguishable—is scientifically meaningless: probative value, considerable prejudicial impact.”68 described that, rates, properly date.69 alone deeply disturbing, prominence prosecutions past years. generous enough permit technique Indeed, participating knew important field. They likely cautious drop study, question challenging feared making error. studies—the published—a huge group, eighty-five least false negative error.70 These provided another overdue wake-up call. shock jurors convictions.71The similarly needs “to confirm fundamental basis bite mark comparison.”72 said uniqueness human dentition “not established.”73 who wrote since valid rates done, validity used.74 What detailed.75 None blunted standard marks delivered court, dentists habit describing reports testimony; indeed, trials.76Of particular importance investigations, violence major States, demand. analysis, seek link spent shell casings bullets, firearm.77 assumption manufacturing processes leave markings barrel, breech face, firing pin. When discharges, components contact ammunition it.78 Experts assumed toolmarks definitively linked single firearm.79 late 1990s, premised “theory identification” professional association, Firearms Tool Mark Examiners (AFTE), instructs practitioners phrase explain mean identify “sufficient agreement” firearms.80 AFTE’s theory circular: identification occurs finds sufficient find identification.81 testimony. 2008 ballistics imaging, (NAS) definitive associations supported.82 report, stated categorical instead, claims made.83 “scientific knowledge base tool fairly limited.”84 AFTE “is inadequate does reach level confidence conclusion.”85By 2016, black box showed rate 1 46.86 unpublished, raises many concerns participants aware assignment materials.87 inconclusive thirty-three percent.88 day, terms court—and avoid Some wording conclusions.89 needed, next, laboratories regulated.There agencies. better documentation, methods, controls, broadly system. protocols work; detectives patrol higher documentation adopt periodic testing, which, theory, examines individually under conditions.90 Crime offer policing, though traditionally fallen short oversight, offers lessons generally.The summarized affairs facing 2009: “Forensic facilities exhibit variability capacity, staffing, certification, across jurisdictions.”91 “Rigorous mandatory certification programs, robust standards, oversight”92 lacking. Moreover, nonpublic.93In contrast, regulations health goals. World War II, experiment Pennsylvania errors, correctly diseases. 1967, Congress Clinical Laboratory Improvement (CLIA) conduct tests.94 wave reform mid-1980s, reporters Wall Street Journal misdiagnosed cancer lax Pulitzer Prize–winning series.95 1988, amendments CLIA extending practically laboratories, not. extent practicable … normal conditions” realistic.96 permitted “announced unannounced on-site individuals.”97 all, lawmakers concluded, “regular [is] vital laboratory’s competence.”98The swift responses failures tepid failures. legislation imposed labs. level, commissions, modest way.99 Maryland licensing 2007 discredited falsified academic credentials, resulting 4,000 cases.100 response, adopted CLIA, laboratories.101 statute accompanying provide laboratories; however, effectiveness regulatory enforces unclear, persisted, examinations, originally prompted regulations.102As nonexistence “lacked measures detected” uses “questionable evidence.”103 national accredited; otherwise, voluntary.104 strongly providers (FSSPs) become compliance industry best practices, standardization, services.105 Bar Association, similarly, recommendation: “Crime accredited, certified, standardized validity, reliability, timely evidence.”106 far common among laboratories.107 minimal exist paper, reliable consistent practice. Thus, “demanding written continuing education, recertification procedures, ethical code, disciplinary procedures” analysts.108 Scientists comprehensive system, person’s life liberty stake, none established.The treated function. undermined fairness. Innocent convicted, guilty free. Quality caused enormous victims, lives wrongly convicted. scenes instead enlisting scientists. incarcerated unregulated tested. otherwise broadly. come guidance Fortunately, models large-scale changes Independence, handled staff dramatically justice