A defense attorney shot up from his chair in protest. This was a murder trial. There was no mirror at the crime scene. No medicine dropper. The demonstration was not reliable science, he argued. The judge disagreed.
MacDonell’s testimony would be pivotal to proving the Fort Bend County prosecutor’s theory that 21-year-old Reginald Lewis had murdered his family, shooting his mother and two brothers and setting his father on fire. MacDonell had identified dozens of minuscule blood spots on Lewis’s clothing, and he said they placed Lewis at the scene during the crime.
The jurors gave Lewis four 99-year sentences.
“MacDonell kind of took over the courtroom,” Lewis’s attorney, Donald Bankston, recalled, his disbelief still fresh. “It was almost like having Mr. Wizard.”
But MacDonell’s testimony that day did more than mesmerize the jury. It gave bloodstain-pattern analysis its first toehold of legitimacy in Texas courts, spreading it quietly, but surely, further into the justice system.
Two years later, Texas’s First Court of Appeals ordered a retrial because of evidentiary flaws (two retrials ended in hung juries), but it expressly rejected Lewis’s argument that bloodstain-pattern analysis was a “novel technique” that should never have been admitted and was not “scientifically recognized” or reliable.
“MacDonell’s studies are based on general principles of physics, chemistry, biology, and mathematics, and his methods use tools as widely recognized as the microscope; his techniques are neither untested nor unreliable,” Judge James F. Warren wrote for the court. To support his decision, Warren cited four other states—Tennessee, California, Illinois, and Maine—that had already affirmed bloodstain-pattern analysis’s use at trial. Two of those states had based their decisions on court testimony by MacDonell.
Warren’s hearty defense of MacDonell and his methods percolated through Texas’s courts, reassuring hundreds of the state’s judges that bloodstain-pattern analysis was reliable enough to be admitted at trial. They would allow it, again and again.
Over time, a parade of spatter experts, often trained by MacDonell—or by someone he trained—dazzled juries across the country with their promise of scientific surety, often tying bows of certainty on circumstantial evidence. Judges in Minnesota, Idaho, and Michigan would rely on the Texas court’s decision when deciding to admit blood spatter in their own states in the 1990s. Those decisions, in turn, would be relied upon by other states.
Blood-spatter testimony spread through courtrooms across the country like a superbug.
Its path—the steady case-by-case, decision-by-decision acceptance of a new forensic science by the justice system—is one that’s rarely, if ever, been retraced. But it reveals the startling vulnerability of judges, and juries, to forensics techniques, both before and after they’ve been debunked.
Although the reliability of blood-spatter analysis was never proven or quantified, its steady admission by courts rarely wavered, even as the technique, along with other forensic sciences, began facing increasing scrutiny.
In 2009, a watershed report commissioned by the National Academy of Sciences cast doubt on the whole discipline, finding that “the uncertainties associated with bloodstain pattern analysis are enormous,” and that experts’ opinions were generally “more subjective than scientific.”
Still, judges continued allowing spatter experts to testify.
Subsequent research, funded by the Department of Justice, raised questions about experts’ methods and conclusions. But little changed.
All along, attorneys like Bankston continued challenging the admission of bloodstain-pattern analysis. But they came to learn that a forensic discipline, once unleashed in the system, cannot easily be recalled.
[ THE BIRTHPLACE OF BLOOD SPATTER ]
About a four-hour drive northwest of New York City, down a quiet winding road, a house with bright red siding peeks through the trees, nondescript except for its fitting hue. At first glance, the home is typical. A side door opens into an overstuffed kitchen, where a stairwell descends to the lower level.
Down those steep stairs, in a sprawling warren of rooms, forensic history was launched more than a half century ago.
Modern American blood-spatter analysis didn’t originate in a federal crime laboratory or an academic research center. It started in Corning, New York, in MacDonell’s basement. Decades before blood-spatter analysis gained fame in TV series like CSI: Crime Scene Investigation or Dexter, MacDonell spent countless hours in his home laboratory, incubating and refining the technique.
Then he spent a lifetime helping it spread.
MacDonell built his first basement laboratory in 1935, when he was seven, setting up some test tubes on a marble slab by the furnace in his childhood home.
But it wasn’t until the 1950s, when he was pursuing a graduate degree focusing on analytical chemistry, that he got a firsthand taste of real forensics while working in a Rhode Island state crime laboratory. After graduating, MacDonell took a stable job as a chemist for the local corporate giant Corning Glass Works, best known for its CorningWare casserole dishes. But in his off hours, he taught forensics at a nearby community college and began moonlighting as a consultant.
In 1968, the focus of MacDonell’s career began to narrow when he testified for a defendant in a New York murder trial. Steven Shaff, a veterinarian, had shot a former employee but claimed it was an accident. The prosecution said the man was sitting in his car when Shaff shot him. Shaff said the victim had thrown open the car door and knocked the muzzle of Shaff’s gun, discharging it accidentally.
When MacDonell studied the crime scene, he found blood spattered along the inside edge of the car door—an area only exposed when the door was open. It was proof, MacDonell testified, that Shaff’s story was true. The jury still found Shaff guilty of manslaughter. MacDonell was disappointed, but the case was a revelation: he could decipher a crime through blood left behind—and it whetted his appetite for more.
A year later, MacDonell successfully applied for a Department of Justice grant to continue his study of bloodstains. In 1971, the DOJ published his findings in a report titled “Flight Characteristics and Stain Patterns of Human Blood.” It would come to be known as the founding text of modern American bloodstain-pattern analysis, and its author the preeminent expert.
MacDonell described blood spatters as a long-overlooked well of information. With a trained eye and a “natural scientific attitude,” he believed, investigators could analyze bloodstains at crime scenes to determine critical evidence such as where the victim was standing during the bloodshed and the kinds of blows—punches, shots, stabbings—inflicted. He documented his work in pages and pages of photographs of blood spattering on different surfaces: neat circles on a plastic wall tile, sprawling splotches on a kitchen towel.
In his report, MacDonell openly acknowledged the accuracy of his methods could not be quantified. “Final conclusions should be considered from the legal viewpoint of ‘proof within a reasonable scientific certainty,’” he wrote in the introduction. “Little attempt has been made to express data in this report in a statistical manner.”
The uncertainty did not slow his momentum.
Propelled by the report’s publication, MacDonell traveled to conferences and industry meetings presenting his research. He piqued the interest of prosecutors, defense attorneys, and police officers, who heard him, then hired him. Satisfied customers spread the word of his unnerving but seemingly useful techniques.