Ed. Note: Chris Halkides has been kind enough, again, to try to make us lawyers smarter by dumbing down science enough that we have a small chance of understanding how it’s being used to wrongfully convict and, in some cases, execute defendants. Chris graduated from the University of Wisconsin-Madison with a Ph.D. in biochemistry, and teaches biochemistry, organic chemistry, and forensic chemistry at the University of North Carolina, Wilmington.

In 1991, Gregory Taylor was partying with an acquaintance when his Nissan Pathfinder got stuck in the mud in Raleigh, NC. About fifty yards away from his vehicle was the lifeless body of Jacquetta Thomas, which Taylor and his casual friend saw but did not report.  When he returned to retrieve the truck, Taylor and his companion were arrested for her murder.

There were two primary pieces of evidence against him, a prostitute who claimed that she had seen the victim get into his vehicle and a spot in the wheel well of his car, which a report from the NC State Bureau of Investigation’s crime lab said gave “chemical indications for the presence of blood,” In 1993, Taylor was convicted of the murder and sentenced to life in prison.

The test in question, the Kastle-Meyer test, is actually a test for peroxidase activity (the ability of a substance to speed up a particular chemical reaction), which hemoglobin, the most abundant protein in red blood cells, happens to have.  However, metal ions (including iron, copper, and manganese) often give positive results in similar tests.

Thus, Kastle-Meyer is one of several presumptive tests for blood. A negative result in a presumptive test rules out the presence of the substance. In order to be certain that blood is present, however, a confirmatory test must be performed with positive results.  A common confirmatory method at the time was the Takayama test.  Presumptive tests are preclusive; confirmatory tests are conclusive.  A separate test for the species origin of blood was also needed to rule out animal blood.

What had not been disclosed during the 1993 trial was that the results of the confirmatory Takayama test were negative.  Two of Gregory Taylor’s attorneys found this information in SBI agent Duane Deaver’s bench notes.  A test for DNA was also negative, but its forensic interpretation in relation to the test for blood is open to debate.

Taylor had exhausted his appeals when in 2009 the North Carolina Innocence Inquiry Commission, the first body of its kind in the country, unanimously voted that his case should be put before judicial review.  In 2010, a three-judge panel exonerated Taylor, and he was pardoned by the governor. According to Duane Deaver, he was following the policy of the laboratory with respect to his reports.  This is partially true; other analysts wrote reports that were also misleading. The Taylor case also prompted NC Attorney General Roy Cooper to appoint former FBI agents Chris Swecker and Michael Wolf to review the practices of the state’s crime lab.

Chris Swecker wrote that the problems resulted from “poorly crafted policy; lack of objectivity; the absence of clear report writing guidance; inattention to reporting methods that left too much discretion to the individual Analyst; lack of transparency; and ineffective management and oversight…”  The Raleigh News and Observer quoted Jed Taub, a 30-year veteran of the SBI:  “’We didn’t report the negative result of a confirmatory test because, really, it’s misleading,’ said Taub, who now works as a forensic investigator for the Pitt County Sheriff’s Office. ‘We couldn’t be sure it wasn’t blood, so those tests really didn’t matter.’”

Deaver and Taub’s words were wrong.  The positive presumptive test only indicated the possibility of blood. The negative result of the confirmatory test meant that one cannot say that blood was present.  In addition the human species test was also negative: even if blood were present, it might have been animal blood.

After Taylor was exonerated, the NC legislature held hearings.  The president-elect of the ASCLD-LAB Jill Spriggs, responding to a question, said, “That is an accurate statement. A lot of times you got no results. It didn’t mean it wasn’t blood; it meant you didn’t have enough sample, or maybe the sample was old. …What else is red-brown that will give you a positive presumptive test for blood? There’s nothing that I know.”  This statement is wrong; rust and soybean root nodules have or can produce a similar color and will give a positive result in the Kastle-Meyer test.

It is also troubling because it suggests that some workers still do not understand that no other test (including DNA profiling) can provide the information that a confirmatory test does.  At least one commercially available test combines the species and confirmatory tests into a single experiment; I cannot think of a good reason not to use it.

Nor is the Gregory Taylor case unique, either in North Carolina or elsewhere.  One of the most damning pieces of evidence against Australia’s Lindy Chamberlain (the dingo case) was a related presumptive test for blood, the ortho-tolidine test.  Chamberlain was convicted for the murder of her infant daughter, Azaria.

This test produced a false positive, probably owing to copper ore dust that was common in the area in which the Chamberlain family lived. Some of the false positives were found in places in the Chamberlain’s car that were inaccessible to putative blood spray.  Chamberlain also exhausted her appeals but was ultimately exonerated after a chance finding of an article of Azaria’s clothing near a dingo lair.

For Further Reading

Christopher Halkides and Kimberly Lott “Presumptive and

Confirmatory Blood Testing” in Forensic Science Reform (2017).

Mike Klinkosum “State v. Taylor and The North Carolina State Bureau of Investigation Lab Scandal”  The Champion May 2011, pp. 10-16.