When Victor Reyes went on trial for murder
last year, the technology that fingered him was supposed to be a star
Police in Florida had used software known as More Hits to determine that
a smudged handprint they had found on duct tape wrapped around a body
— but originally couldn’t decipher — implicated Reyes
in the 1996 killing.
But the defense had an art professor testify that the process resembled
how Adobe Photoshop can be used to make trick photo illustrations.
Hector Hernandez of the Oregon State Police examines
a digital image
of a fingerprint on a pop can in a lab in Salem. Critics note it's easier
manipulate digital images than film. (Don Ray/Associated Press)
Reyes was acquitted.
Jurors said they based their decision mainly on the notion that the print
didn’t prove Reyes was the killer — not on the legitimacy
of More Hits’ method. And a Florida appeals court later ruled that
More Hits’ technology — used by 215 U.S. police departments
— is acceptable.
Still, some defense attorneys learned a lesson: Get more aggressive about
challenging digitally generated evidence.
“Now, whenever you hear the word enhancement, an antenna goes up,”
said Hilliard Moldof, a Florida defense attorney who is questioning digitally
enhanced fingerprints in two cases.
As more police departments abandon chemically processed film in favor
of digital photography, the technology could be confounding for the justice
Film images are subject to darkroom tricks, but because digital pictures
are merely bits of data, manipulating them is much easier.
And although willful evidence manipulation is rare, forensic specialists
acknowledge that a poorly trained examiner incorrectly using computer
enhancement programs can unwittingly introduce errors.
“What you can do in a darkroom is 2 percent of what Photoshop is
capable of doing,” said Larry Meyer, former head of photography
for State Farm Insurance Co.
Courts have consistently allowed digital photographs and enhancement techniques.
But some observers say such methods should endure a more thorough examination,
such as DNA analysis.
“There have been relatively few challenges to the use of digital
technology as evidence, and in most of them, the courts have looked at
them in a fairly superficial way,” said Edwin Imwinkelried, an evidence
expert at the University of California-Davis law school.
Concerns about the impeachability of digital photographs are one reason
many police departments have been hesitant to ditch film for crime scene
photographs and forensic analysis.
In fact, some people who train law enforcement agencies in photography
estimate that only 25 to 30 percent of U.S. police departments have gone
digital — despite the huge cost benefits of no longer having to
buy film and the ease with which digital pictures can be captured and
The police department in Santa Clara, Calif., bought 30 digital cameras
recently but is holding off on giving them to detectives and technicians
until the department specifies ways to lock away the original photos as
evidence “so there can be no question that anything was changed,”
said Sharon Hoehn, an analyst for the department.
George Pearl, who runs an evidence service for civil cases in Atlanta
and is a past president of the Evidence Photographers International Council,
sticks with film partly because he doesn’t want to explain on a
witness stand if he used a computer to adjust the contrast and other settings
of a digital image, “even if it was honest adjustments,” Pearl
said. “Juries, they’re all skeptical, and they’re all
sitting there waiting to jump on something that’s wrong.”
Some law enforcement officials worry about the limitations that still
plague digital photography.
Digital pictures can’t be blown up as clearly for courtroom displays
as film photos can. Or the compression needed to store a digital file
on disk can make the image blurry or blocky, potentially obscuring key
“Digital imaging for the most part has a long way to go to meet
the quality of film,” said Richard Vorder-Bruegge, an FBI forensic
expert who chaired a panel that wrote guidelines for law enforcement use
of digital imaging.