The science of biometrics is exactly what it sounds like — measurement of the living body, including quantification of such physical characteristics as fingerprints, eyes, and voice. But in recent years it has come to be associated most immediately by laypersons with one particular type of biometric analysis: facial recognition.
In the years after the terrorist attacks of Sept. 11, 2001, techniques for precisely identifying strangers by their most public and easily recorded attributes — their faces — seemed to hold great promise as a means for improving national security. If terrorists at airports, shopping malls, or government buildings could be easily picked out when their images appeared on surveillance cameras, then other ruses for bypassing security safeguards, such as phony passports or birth certificates, could be foiled.
That was the promise. The reality has consisted largely of disappointment. While the U.S. Department of Homeland Security and the Department of Defense remain bullish on the future of facial biometrics — the latter has poured hundreds of millions of dollars into research and development of face-recognition techniques — the technology has yet to live up to its early hype during the post–9/11 period.
Police departments in Florida and Virginia have abandoned facial-biometrics surveillance systems that did not yield any arrests while they were deployed. Several years ago, a surveillance experiment at a train station in Mainz, Germany, found that automated facial recognition had a success rate of only 60 percent during the day and as low as 10 percent at night, when poor lighting made identification more difficult. The American Civil Liberties Union has also raised questions about the government's research into facial recognition, arguing that the technology violates privacy and often produces mismatches.
As a result, facial-identification biometrics has failed to gain widespread acceptance in the law-enforcement and scientific communities for most uses. But last month in San Francisco, it was abruptly adopted for a task far more specific — and arguably more serious — than those for which it has been considered in the past: the identification of a killer.
In what legal and scientific experts say is a groundbreaking case, a San Francisco Superior Court judge allowed biometric facial-identification technology, along with accompanying testimony from an expert witness, to be admitted as evidence in a high-profile criminal trial.
And in a curious turn, biometrics — the science popularized for its use in attempts to catch terrorists — was being used in San Francisco to try to exonerate an accused gang member and murderer.
The case was that of Charles "Cheese" Heard, 25, an alleged Western Addition gangster accused of murdering San Francisco resident Richard Barrett during an attempted robbery in North Beach on Nov. 25, 2008.
Business surveillance cameras captured footage of the man who probably shot Barrett, as well as an accomplice. Heard's defense team persuaded a judge to allow testimony from an expert who argued, based on a biometric comparison of still frames from the video and photos taken of Heard while he was in jail, that the defendant could not be the same person as the shooter.
This was an unusual development for a couple of reasons. It's uncommon for criminal-defense attorneys to seek to have new scientific evidence admitted to court; far more often, it is prosecutors who try to foist novel techniques for identifying suspects on jurors, as viewers of TV's Forensic Files can attest. In the case of biometrics, the irony was particularly striking, since most of the technology's previous applications have been in settings where it was used to screen and apprehend suspects, not to set them free.
More significantly, Heard's case could serve as a precedent — albeit not a legally binding one, since it was not ruled on by the state's appellate or supreme court — for the future use of facial-identification technology in criminal trials. In a motion opposing the defense's efforts to present its biometrics analysis to the jury, Assistant District Attorney Michael Swart noted that no California appeals court has ever ruled on whether this form of technology could be used as evidence.
David Faigman, an expert on scientific evidence at Hastings College of the Law in San Francisco, said the judge's decision to allow facial-recognition techniques into the courtroom was a surprise, since the technology appears not to meet a few basic legal standards applied to other forms of scientific evidence, such as DNA or fingerprint analysis.
Faigman said that given how little we know about the reliability of facial-identification biometrics, the admission of such evidence in Heard's trial could be seen as a troubling development, particularly if other judges accept the case as a precedent for future trials.
"I think it is precedent-setting," he said in an interview. "But I also think that the appellate courts might take a dim view of the admission of this evidence. ... Without the systematic and rigorous evaluation of the evidence, it's hard to know how much weight to give it."
Nonetheless, biometrics was set to play a starring role in front of an audience of San Francisco jurors in the Heard trial. Would they deem the technology good enough to help set an accused murderer free?
Richard Barrett was 29 years old when he was killed shortly after leaving Larry Flynt's Hustler Club, a well-known gentleman's club off a notoriously vice-ridden and violent strip of Broadway in North Beach. According to cops and prosecutors, Barrett was shot twice in the back by thieves trying to steal one of his prized possessions: a jewel-encrusted pendant depicting the cave-baby Bamm-Bamm from The Flintstones.
"Bam bam" is street slang for cocaine, and during Heard's trial, his defense attorney, Eric Safire, argued that Barrett, while the victim of a tragic crime, was a criminal himself. According to Safire, Barrett sold drugs and mingled with the characters — strippers, whores, pimps, gangbangers, and the boozy bridge-and-tunnel crowd — who walk Broadway's streets after dark. "He was selling cocaine," Safire told the jury. "It could have been a bad drug deal ... somebody could be mad he's pimping their girlfriend."