Nevertheless, a problem remains. Mr. Spence was almost certainly innocent.
This is not a hypothesis conveniently floated by death-penalty opponents. Those who believe that David Spence did not commit the crime for which he died include the lieutenant, now retired, who supervised the police investigation of the murders; the detective who actually conducted the investigation, and a conservative Texas businessman who, almost against his will, looked into the case and became convinced that Mr. Spence was being railroaded.
The retired lieutenant, Marvin Horton, said in sworn testimony: ”I do not think David Spence committed this crime.”
In an interview Wednesday, Ramon Salinas, the homicide detective who investigated the murders, said: ”My opinion is that David Spence was innocent. Nothing from the investigation ever led us to any evidence that he was involved.”
The businessman, Brian Pardo, was asked for help by Mr. Spence last fall. ”The probability of him being innocent seemed very small in my mind at that time,” Mr. Pardo said. ”He was on death row. It just seemed to me that most people there are guilty, and they all say they are innocent.”
Mr. Pardo agreed to underwrite an investigation that would last only until some evidence turned up showing that Mr. Spence was guilty. No evidence ever did.
”It was all entirely to the contrary,” Mr. Pardo said. ”There is no chance that he committed those murders.”
The murders were horrifyingly violent and bloody. There was a great deal of contact between the victims and the killers. But there was no physical evidence connecting the crime to Mr. Spence or his co-defendants, both of whom are incarcerated for life.
Strands of hair, including pubic hairs, that most likely came from the killers were found on the victims. But an F.B.I. analysis determined that none of the hairs came from Mr. Spence or his co-defendants.
The case against Mr. Spence was pursued not by homicide detectives but by a narcotics cop named Truman Simons who left the Police Department under unusual circumstances, went to work for the county sheriff and in that capacity conducted an obsessive, unprofessional and widely criticized campaign to nail Mr. Spence. (There will be more about this in future columns.)
Mr. Simons cobbled his case together from the fabricated and often preposterous testimony of inmates who were granted all manner of favors in return. Court papers showed that some were even given the opportunity to have sex with wives or girlfriends in the district attorney’s office.
October 2015 Summary Texas Monthly via Wrongful Conviction Blog : ( “Bite Mark Analysis” )
The third case is even more troubling because it involved an execution. The defendant’s name was David Spence, and he was, oddly enough, Juanita White’s son. (For more on this labyrinthian case read “The Murders at the Lake.”) Spence was convicted in two trials, in 1984 and 1985, of the murders of three Waco teens and given the death penalty. The only physical evidence against him: bite marks on the bodies of two of the victims. The expert who testified: Homer Campbell. Spence, Campbell said, was “the only individual” to a “reasonable medical and dental certainty” who could have bitten the women. According to jurors, Campbell’s words were powerful. “We had life-size pictures of the marks and a cast of [Spence’s] teeth brought into the jury room,” remembered one juror afterward. “The testimony—‘everyone’s bite mark is different, like a fingerprint’—was very convincing.”
Spence’s appellate lawyers tried to attack Campbell’s methods with other forensic odontologists. One, Thomas Krauss, a former president of the American Board of Forensic Odontology (ABFO), said Campbell’s methodology was “well outside the mainstream.” Krauss helped the lawyers set up a blind panel of five odontologists to analyze the autopsy photos and vet Campbell’s work by comparing the marks with dental molds from Spence and four other subjects. The results were astonishing. Though the five experts identified several patterns that were possibly bite marks, they couldn’t say much more. One of them said the photos were too poor in quality to compare to the molds. A second wrote that the marks were “more likely than not made by insects or artifacts.” A third thought that some of the marks were probably bite marks, but he couldn’t match any of the molds to them. Two of the experts did indeed match one of the marks to one of the molds, but it was not Spence’s. It belonged to a housewife from Phillipsburg, Kansas. Unfortunately for Spence, the study wasn’t completed until after the deadline for Spence’s writ. He was eventually executed, despite numerous questions about his guilt—the biggest coming from the fact that the only physical evidence against him came from Campbell.