How 'Dexter,' 'CSI' And Henry Lee Convinced Juries To Buy Blood Spatter Analysis

When "Dexter: New Blood" premieres on Showtime on Nov. 7 — the show's first new episodes since the original series ended in 2013 — the titular character will have a new name (Jim Lindsay) and a new day job (hunting store employee). And given developments in forensic blood spatter analysis – Dexter's previous day job –  that might be for the best.

Though neither the Dexter of the book series (which was first published in 2004) nor of the show (which premiered in 2006) was reportedly based on a real-life blood spatter analyst, at that time, the most famous blood spatter analyst in pop culture was probably on the CBS series "CSI," which premiered in 2000. On that show Marg Helgenberger played Catherine Willows for 12 seasons: a stripper-turned-lab-tech who became a blood spatter expert and a supervisor of that show's team.

The "CSI effect" — in which juries were thought to be dismissive of criminal cases with no physical evidence — has been disproven in large part, but most researchers in the field agree that "CSI" and other shows like it have had a demonstrable effect in jurors' understanding of physical science — and their trust in it.

In real life, arguably the most recognizable blood spatter expert at the time was (and is) Dr. Henry Lee. Lee, who is currently the director of the Forensic Research and Training Center at the Henry C. Lee Institute of Forensic Science at the University of New Haven in Connecticut, served as that state's chief criminalist, the director of state police forensic laboratory and the state director of public safety during his 20+ year tenure with the state. In 2004, his eponymous show, "Trace Evidence: The Case Files of Dr. Henry Lee," premiered on what is now truTV and lasted for two seasons.

While Lee predominately testified for the prosecution in various cases, he also occasionally testified for some defense teams. 

He established himself professionally when his analysis of materials found on a lake shore helped convict Richard Craft of the murder of his wife, Helles Craft in 1986; Richard Craft was accused of killing his wife and disposing of her remains via a woodchipper. His conviction successfully marked the first time Connecticut had prosecuted a murder without a body.

In the years after, he testified or worked in a number of high profile cases, including for the defense at O.J. Simpson's trial for the murders of Nicole Brown Simpson and Ron Goldman, in Ken Starr's federal investigation into the suicide of Vince Foster, and for Scott Peterson's defense after he was charged in the murder of his wife, Laci Peterson. (He told the Associated Press in the mid-90s that his work for defendants "supplemented" his income from the state of Connecticut.)

Later, however, his analysis and conduct was called into question, The Daily Beast  reported in 2019. He was admonished by a judge in 2007 for his work for Phil Spector's defense in the murder of Lana Clarke after the judge determined that he had taken evidence from the crime scene and not turned it over (Lee denied doing so, and Spector was convicted). He is currently being sued by two men, Ralph Birch and Shawn Henning, whose convictions in the 1985 murder of Everett Carr was thrown out last year: Lee had testified that a substance on a towel found at the scene was blood, though the state Supreme Court later determined that he'd never tested in in his lab. (Lee said it was presumptive for blood in tests at the scene, though he testified to something slightly differently at the time, according to the Washington Post.) And, in 2017, the state of Connecticut agreed to modify the sentence of and release David Weinberg, who had been convicted of the 1988 murder of Joyce Stochmal based on evidence, presented by Lee, that Weinberg had human blood on his knife. The blood on his knife was not human.

But the current skepticism about Lee's work in blood spatter analysis is more widespread than just Lee, himself. 

In 1995, the state of North Carolina Supreme Court ruled that blood spatter analysis was admissible in court as part of the case State v. Goode, in which Goode was convicted, in part, by evidence developed by state forensic analyst David Deaver. But in 2011, Deaver was fired from the state crime lab after an investigation found more than 200 improperly handled cases and attributed the worst of them to Deaver. (One of those cases was that of author Michael Peterson, who had been convicted of the murder of his wife Kathleen Peterson in 2001 based in part on Deavers' testimony. Lee testified for the defense in that case. Peterson was retried post-Deavers and eventually entered an Alford plea. 

And in 2009, the National Academy of Sciences issued a report about strengthening forensic analysis in which they noted that blood spatter analysis was more complicated than it seems and most analysts were ill-prepared to perform it.

"However, many sources of variability arise with the production of bloodstain patterns, and their interpretation is not nearly as straightforward as the process implies," states the report. And, noting that most training in the field comes from workshops, the report continues, "Bloodstain patterns found at scenes can be complex, because although overlapping patterns may appear simple, in many cases their interpretations are difficult or impossible."

"Workshops teach the fundamentals of basic pattern formation and are not a substitute for experience and experimentation when applying knowledge to crime reconstruction."

In 2018, a lengthy feature by ProPublica and the New York Times called blood spatter analysis "dubious," noting that the scientist who first developed the field was not employed as a forensic analyst at the time and, in 2012, was charged with the sexual abuse of two minor girls and pled guilty to harassment charges.