Chapter 7 Scientific and Forensic Evidence

• Jurisdiction: United States

Chapter 7 Scientific and Forensic Evidence

A. Introduction

On March 11, 2004, terrorists' bombs claimed 191 lives and injured thousands more when they exploded on trains operating in Spain's capital city, Madrid. Because American citizens were among the casualties, the FBI became involved in the investigation. Spanish police found fingerprints on a bag containing detonation materials linked to the bombings and electronically transmitted images of them to the FBI's crime laboratory in Quantico, Virginia. There, investigators concluded that the latent fingerprint images secured from the bag were a "100 percent match" with the fingerprints of Brandon Mayfield, a 37-year-old Portland, Oregon lawyer and convert to Islam whose clients included a man recently convicted on federal terrorism charges. Mayfield was arrested as a "material witness" to the bombings on May 6, 2004. He was incarcerated for two weeks, while law enforcement authorities obtained a warrant to search his law office, including his business files. In the meantime, Spanish police had independently examined the fingerprint evidence and disagreed with the FBI's analysis; they concluded that Mayfield's fingerprints did not match those found on the incriminating bag. On May 24, 2004, the United States government acknowledged that the FBI's fingerprint identification was erroneous and dismissed the charges against Mayfield. More than two years later, the government apologized to Mayfield and his family and paid him $2 million in damages for his wrongful arrest.¹

In some respects, Mayfield was lucky. Although he was jailed, suffered a loss of privacy through the searches of his office and files, and incurred the reputational damage associated with being a suspected terrorist, the flawed fingerprint analysis did not result in his wrongful conviction. Others have experienced far greater hardships because of faulty forensic evidence. For example, Stephen Buckley, whose case we presented in Chapter 2 (Buckley v. Fitzimmons, 509 U.S. 259, 113 S.Ct. 2606, 125 L.Ed.2d 209 (1993)) on the issue of prosecutorial immunity from damages under 42 U.S.C. § 1983, was arrested and brought to trial for capital murder in Illinois. The charges against him eventually were dismissed after his trial resulted in a hung jury, but not until he spent nearly three years in jail. "The principal evidence against him [at his trial] was provided by [Dr. Louise] Robbins," an anthropologist "who was allegedly well known for her willingness to fabricate unreliable expert testimony." Id., 509 U.S., at 263-264.

Robbins had noticed that people wear down the bottoms of their shoes in various ways because they walk differently. Some people wear down the outside of the heel first, for example, while others rub away the inside. She also knew that the bone structures of people's feet vary. Robbins decided this meant each individual has a unique "wear pattern" that could be used to match a person to any of his or her shoeprints, even if they changed shoes.... [S]he claimed she could determine the sex, race, and socioeconomic status of a person just by looking at a shoeprint.²

Robbins' testimony was crucial. "[T]hree separate studies by experts from the Du-Page County Crime Lab, the Illinois Department of Law Enforcement, and the Kansas Bureau of Identification, all ... were unable to make a reliable connection between" a bootprint left on the front door of the home from which the murder victim—a 10-year-old child—had been abducted, and Buckley's boot. Buckley v. Fitzimmons, 509 U.S., at 262. Robbins, conversely, had no hesitation in opining that the print left on the door matched Buckley's boot. The problem, however, was that Robbins' testimony was wrong. Neither her theory nor the methodology she used in making her analyses had any basis in science. Two of Buckley's co-defendants, Rolando Cruz and Alejandro Hernandez, were convicted and sentenced to death for the murder that the three men had been accused of jointly committing. They subsequently were exonerated. Brian Dugan, who was linked to the murder by DNA evidence and confessed to having committed it alone, later pled guilty to the crime.³

Controversy swirls around whether Texas may have executed two men in error following murder convictions supported by questionable forensic evidence. Cameron Todd Willingham was executed in 2004 for the arson murder of his three children in Corsicana, a small city northeast of Waco. Willingham was at home with his children when the fire broke out. He maintained that the fire's origin must have been accidental and insisted that he was innocent of any wrongdoing. His 1992 conviction depended heavily on the testimony of fire investigators that the blaze that engulfed the home had been set intentionally. Scientists and arson investigation experts have since cast doubt on the validity and scientific bases of those conclusions.⁴

Claude Jones was convicted for a robbery-murder committed in a liquor store near Houston in 1989. His conviction was supported by a forensic expert's testimony that a hair found at the crime scene "matched" Jones's hair. The expert's conclusion also was used to corroborate the trial testimony of an alleged accomplice that Jones had committed the murder. Jones maintained his innocence. The purported accomplice subsequently admitted that he had lied. Jones was executed in 2000. A posthumous mitochondrial DNA analysis of the hair in question, completed in 2010, excluded Jones as its source and instead pointed to the hair belonging to the murder victim.⁵

According to the Innocence Project, problems with forensic science evidence have figured in 45% (162/358) of the convictions upset with the help of DNA through August 1, 2018, making this category the second most common contributing factor to the identified wrongful convictions.⁶ An analysis of the 325 DNA-based exonerations chronicled between 1989 and 2014 identified problems involving multiple forensic techniques, including serology (a factor in 84, or 55% of the 154 cases in which misapplication of forensic science contributed to a wrongful conviction), hair sample comparisons (a factor in 73, or 47% of the cases), bite mark analysis (in 9, or 6% of the cases), DNA testing (in 8, or 5% of the cases), reliance on dog scent (6, or 4% of the cases), fingerprint identification (3, or 2% of the cases), and others (10, or 6% of the cases).⁷ The National Registry of Exonerations identifies "false or misleading forensic evidence" as contributing to nearly a quarter (541/2253, or 24%) of wrongful convictions resulting in exonerations between 1989 and August 1, 2018.⁸ There is no question that forensic evidence can be highly probative and help establish both guilt and innocence. Yet its misuse or misinterpretation, including testimony overstating its conclusiveness, also can help produce wrongful convictions.

In 2009, a distinguished panel of experts commissioned by the National Academy of Sciences (NAS) issued a comprehensive report focusing on the forensic sciences and the use of forensic evidence in court, Strengthening Forensic Science in the United States: A Path Forward.⁹ The report addressed numerous issues, including:

(a) the fundamentals of the scientific method as applied to forensic practice—hypothesis generation and testing, falsifiability and replication, and peer review of scientific publications;
(b) the assessment of forensic methods and technologies—the collection and analysis of forensic data; accuracy and error rates of forensic analyses; sources of potential bias and human error in interpretation by forensic experts; and proficiency testing of forensic experts;
(c) infrastructure and needs for basic research and technology assessment in forensic science;
(d) current training and education in forensic science;
(e) the structure and operation of forensic science laboratories;
(f) the structure and operation of the coroner and medical examiner systems;
(g) budget, future needs, and priorities of the forensic science community and the coroner and medical examiner systems;
(h) the accreditation, certification, and licensing of forensic science operations, medical death investigation systems, and scientists;
(i) Scientific Working Groups (SWGs) and their practices; (j) forensic science practices—

pattern/experience evidence
• fingerprints (including the interoperability of AFIS)
• firearms examination
• toolmarks
• bite marks
• impressions (tires, footwear)
• bloodstain pattern analysis

• handwriting
• hair
analytical evidence
• DNA
• coatings (e.g., paint)
• chemicals (including drugs)
• materials (including fibers)
• fluids
• serology
• fire and explosive analysis
digital evidence;

(k) the effectiveness of coroner systems as compared with medical examiner systems;
(l) the use of forensic evidence in criminal and civil litigation—

• the collection and flow of evidence from crime scenes to courtrooms
• the manner in which forensic practitioners testify in court
• cases involving the misinterpretation of forensic evidence
• the adversarial system in criminal and civil litigation
• lawyers' use and misuse of forensic evidence
• judges' handling of forensic evidence;

(m) forensic practice and projects at various federal agencies ... ;
(n) forensic practice in state and local agencies;
(o) nontraditional forensic service providers; and
(p) the forensic science community in the United Kingdom.¹⁰

The NAS report noted the considerable breadth of disciplines nested within the forensic sciences, and the vast differences in their substance and methods as well as among their practitioners.

The term "forensic science" encompasses a broad range of forensic disciplines, each with its own set of technologies and practices.... [T]here is wide variability across forensic science disciplines with regard to techniques, methodologies, reliability, types and numbers of potential errors, research, general acceptability, and published material. Some of

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