Cliff Spiegelman doesn't care to see Oliver Stone's film JFK, a conspiratorial opus about the assassination of President John F. Kennedy. And he has no opinion – at least not one he's willing to share – about whether presumed shooter Lee Harvey Oswald acted alone.
But the Texas A&M University statistician's examination of the forensics in the 1963 slaying led him to conclude that the assertion that Oswald must have acted alone based on the comparative bullet lead evidence has been overstated.
Spiegelman will discuss his research into the bullet evidence of the Kennedy case during a free public lecture set for Friday, Nov. 22 – the 50th anniversary of the assassination – at 4 p.m. in Room 510 Rudder Tower on the Texas A&M campus. He will be joined by William A. Tobin, a former chief metallurgist for the FBI. Spiegelman led a team including Tobin that cast doubt on previous assertions about the strength of the forensic science.
Chemist Vincent Guinn testified to the 1976 U.S. House Select Committee on Assassinations that the recovered bullet fragments came from just two Western-Winchester Cartridge Co. Mannlicher-Carcano bullets that Oswald used, and that they were unique enough to be distinguishable from each other even if they came from the same box. Based partly on that testimony, the committee concluded in 1979 that two bullets hit Kennedy, and they were fired from Oswald's rifle. (Fifteen years earlier, the Warren Commission also concluded that Oswald fired the shots that killed Kennedy.)
Spiegelman and his team of researchers, however, reported in a 2007 paper in the journal Annals of Applied Statistics that they had examined 30 of the same brand of bullets from three boxes and found one of them out of 10 examined from a box of 20 matched the assassination fragments. So whereas Guinn essentially claimed a zero out of 100 chance of other matching bullets, the reality based just on a batch the researchers analyzed was closer to 10 out of 100, Spiegelman said.
"So we're not saying that there's no value to the science presented in the Kennedy case, but simply that it was overstated and not as overwhelmingly certain as it was presented," said Spiegelman, a distinguished professor in the Texas A&M Department of Statistics.
It was the Kennedy assassination that popularized the use of a method of forensic testing called Comparative Bullet Lead Analysis (CBLA), a technique that uses chemistry to link bullets found at crime scenes to the guns from which they were discharged.
Spiegelman was a leading critic of the method. After years of opposition from him and others, the FBI announced in 2005 that it would discontinue use, stating in a news release that "neither scientists nor bullet manufacturers are able to definitively attest to the significance of an association made between bullets in the course of a bullet lead examination."
For Spiegelman, the driver for his research wasn't the Kennedy assassination, but rather the integrity of forensic science as it relates to the criminal justice system.
"If we could show that even in the Kennedy case, which had so many resources and attention devoted to it, the science could still be misleading and oversold," Spiegelman said, "then how many mistakes must occur in the routine, low-profile cases that are being handled by public defenders?"
It's a question that has led Spiegelman to take up forensic science reform in the criminal justice system. Spiegelman often travels across the country – even volunteering his expertise for free – to testify in cases in which he believes the evidence could be misleading. Earlier this year, he also began serving as the only statistician on a panel providing technical advice to the city of Houston in restructuring the city's crime lab.