Trial judges can refuse to hear evidence they deem unreliable. At the appellate level, judges review decisions made at trial and can deem an individual expert unqualified or label a whole field unreliable, banishing it from trial courts below.
Around the turn of the last century, judges rejected precursors to modern bloodstain-pattern analysts. Mississippi’s Supreme Court and the California Court of Appeal both affirmed decisions to exclude blood-spatter experts—in 1880 and 1927, respectively—on the grounds that their analysis added nothing to the jury’s own common-sense inferences.
But courtroom attitudes shifted as MacDonell’s brand of expertise seeped in.
In 1957, California’s Supreme Court accepted blood-spatter testimony from Paul Kirk, a man MacDonell cited as an inspiration. Kirk, a professor of biochemistry and criminalistics at the University of California, Berkeley, had worked on the Manhattan Project and was an early practitioner of bloodstain-pattern analysis. The court wrote that Kirk’s “inferences required knowledge and experience beyond those of ordinary jurors.”
Kirk became the technique’s first flag-bearer. Nine years later, he would use blood-spatter analysis to help exonerate Sam Sheppard, a doctor who had been convicted of killing his wife in a trial so aggressively covered by the news media that the US Supreme Court condemned the “virulent publicity” surrounding it. That same year, the Alaska Supreme Court accepted bloodstain-pattern analysis.
Then came a lull. Kirk died a few years after the Sheppard trial. Appellate courts mostly stopped talking about bloodstain-pattern analysis. Then MacDonell came along.
In 1980, Iowa’s Supreme Court became the first to review MacDonell’s testimony. The judges didn’t examine the accuracy of his technique. Instead, they cited his “status as the leading expert in the field.” Finding his testimony reliable, they noted MacDonell’s discipline had “national training programs”; “national and state organizations for experts in the field”; “the holding of annual seminars”; and “the existence of specialized publications.”
With seals of approval from some of the country’s highest courts, bloodstain-pattern analysis continued its spread.
It moved east, gaining acceptance in an Ohio court of appeals, where both the defense and prosecution presented blood-spatter experts. Then south, as Tennessee’s highest court affirmed a trial judge’s decision to admit MacDonell as an expert. “Mr. MacDonell’s testimony was clear, understandable, and accompanied by demonstrations to the jury,” the court wrote. “He obviously knew whereof he spoke.”
MacDonell’s students carried the technique west to Oklahoma and Illinois. When a defendant argued a police officer who studied with MacDonell did not have a sufficient understanding of science to testify as an expert, an appeals court in Illinois responded, “We again reject the defendant’s argument that this area of expertise requires substantial training in physics.”
In Minnesota, a court affirmed expert testimony that bloodstains could reveal whether a victim was crouching or standing; in Idaho, that the stains showed a victim was walking away when shot.
After a while, some judges facing the issue for the first time simply cited the decisions of their counterparts in other states.
Acceptance of bloodstain-pattern analysis became almost inevitable.
Throughout, a handful of judges expressed concern. In 1980, Judge Mark McCormick of Iowa’s Supreme Court singled out MacDonell in writing. “I am unable to agree,” he wrote, “that reliability of a novel scientific technique can be established solely on the basis of the success of its leading proponent in peddling his wares to consumers.”
Judge Stephen Bistline of Idaho’s Supreme Court, in a vehement dissent in 1991, wrote: “The danger presented by expert testimony interpreting blood-spatter evidence is that the prosecution is provided with an expert who appears to be able to reconstruct precisely what happened by looking at the blood left at the scene of a crime. However, a quick review of the ‘science’ relied upon by the expert suggests that we would be better off proving guilt beyond a reasonable doubt without the help of such experts.”
But the skeptics’ dissents and uneasiness could not contain the spread.
By 2004, a Texas court of appeals wrote: “Have any courts held blood-spatter analysis to be invalid? The short answer is no.”
Over time, growing layers of legal precedent protected bloodstain-pattern analysis, allowing it to flourish unhindered.
Attorneys on both sides began presenting competing experts, assured they would be admitted. Some forensic scientists grew concerned by the number of police officers qualifying as experts based on a mere 40 hours of formal training.
MacDonell deflected responsibility in one of his books. “The fault for permitting such individuals to testify as an expert must rest with the opposing attorney,” he wrote, adding that “a judge should be able to recognize unqualified charlatans.”
MacDonell ran his last Bloodstain Evidence Institute in 2011. By then, he had taught 75 workshops and over 1,000 students. Some of them replicated his business model, running 40-hour workshops of their own. This new wave of blood-spatter entrepreneurs established fiefs in different corners of the country, advertising their services through the IABPA.
In 2012, MacDonell, then 84, retired. That same year, two girls alleged he had sexually abused them when they were 11 and 16. One said the abuse occurred while she was a student at a summer forensics program taught in his home. MacDonell was charged in Corning town court with forcible touching, two counts of endangering the welfare of a child, exposure of a person, and aggravated harassment in the second degree. He pleaded guilty to the harassment and the remaining charges were dropped. MacDonell said recently that he’d done nothing wrong and pled to the charges on “the bad advice of my attorney.”
Afterward, no lawyer could reasonably present MacDonell at trial as he was too easy to undermine on the witness stand. His career as an expert witness was over.
But by that time, the field hardly noticed his absence. Others, many members of law enforcement who’d gotten their start as MacDonell’s students, had taken his place at the forefront of the discipline. And while the technique’s earliest experts, MacDonell and Kirk, had impressed judges with their extensive scientific backgrounds, many of the new wave of experts had little to no scientific education at all.
[ A TECHNIQUE PUTS DOWN TENACIOUS ROOTS ]
In 2006, federal judge Nancy Gertner handed down a sentence that still haunts her.
A jury in her courtroom convicted a man named James Hebshie of burning down his convenience store to fraudulently collect insurance money. Gertner thought the prosecution’s most damning piece of evidence—that a state trooper’s accelerant-sniffing dog identified where Hebshie started the fire—was bogus. But Hebshie’s defense attorney never objected, even when Gertner interjected three times, offering him the chance.
Without arguments before her, Gertner could not exclude the evidence. The mandatory minimum sentence was 15 years, and she had to impose it. “I was appalled,” she said.
Before her 1994 appointment to the bench, Gertner worked for years as a defense attorney, scrutinizing and challenging forensic evidence presented against her clients. She later taught law students about the risks of forensics as a professor of evidence at Boston College Law School. But as a judge, she realized cases like Hebshie’s could render her powerless.