Sun-Sentinel: News Local

Fingerprint technology faces test in court

By Paula McMahon
Staff Writer
Posted December 15 2002

When detectives were investigating the 1996 shooting death of a Pompano Beach man, they found faint handprints on duct tape wrapped around the body. But, at the time, the prints were useless to identify the killer.

That changed last year, when the Broward County Sheriff's Office turned one of the smudges into valuable evidence by using two controversial forensic techniques that prosecutors say reveal hidden clues. Using digital photography and computer software, technicians uncovered a print that was almost invisible to the naked eye.

Some experts say the print implicates Victor Reyes, 33, who already had been charged in 1999 with the first-degree murder of Henry Guzman, based on other evidence.

But defense attorneys say the fingerprint technology crosses the line between uncovering evidence and creating it.

Both methods are on the cutting edge of new forensic tools that are just beginning to be tested in the nation's courts. They are so new that only two appellate courts, in Ohio and Washington state, have ruled that one of them -- digitally enhancing fingerprints -- is scientifically reliable enough to meet legal standards.

The other method, "dodge and burn," which is used to lighten or darken images digitally, has not yet been tested in the courts.

At Reyes' first-degree murder trial early next year in Broward Circuit Court, both new technologies will get their first serious challenge in Florida. Reyes' Fort Lauderdale attorney, Barbara Heyer, has launched the most aggressive attack yet, calling it "junk science." The trial judge has ruled it can be used.

"I think it's very suspicious that you have something that is of no value and suddenly you enhance it and it becomes of value," said Heyer. "It is very clear that this type of thing can be manipulated."

The software used to enhance the print is the same that some tabloid newspapers use to create seamless "photographs" of space aliens hanging out with celebrities. Time magazine used a similar program to alter a police mug shot of O.J. Simpson and make his complexion appear darker on its front page in 1994.

Heyer said that shows the software is not a scientific tool, but an unreliable art form that could be used to misrepresent reality or simply create things.

Added to the mix in the Reyes case is that the print on the duct tape has disappeared. It wore off the tape because it was processed and examined so many times.

The partial print from the duct tape, which experts say matched Reyes' palm, went from being useless, to a match for Reyes, to nothing but a digitally captured image.

"It's nonexistent because it's gone now," said Heyer.

Two FBI experts and one Broward examiner say the palm print matches Reyes'. Another Broward examiner says she will not identify it.

BSO forensic analyst David Knoerlein, who enhanced the print, was not allowed by his supervisors to discuss the specifics of the Reyes' case. But Knoerlein says that enhancement and "dodge and burn" are phenomenal forensic tools.

"There is a big difference between altering and enhancing," said Knoerlein, adding that BSO has strict rules about what can be done to an image. Only certain staff members can access the system and it automatically logs the user and length of use.

Starting with a digital image of a barely visible fingerprint on a check, the software creates a copy and then saves the original image and gives it an encryption code that Knoerlein says would detect if he made alterations.

He goes to work on the copy, which is saved in a separate computer folder and assigned its own encryption code when Knoerlein finishes his work. He uses Adobe Photoshop, a computer program for graphic artists and photographers, and another program, More Hits, developed for law enforcement by a forensic analyst in Tacoma, Wash.

Knoerlein says what he does is like adjusting the contrast on a TV set and trying to make the picture clearer.

The new methods have come in most useful in lifting fingerprints from surfaces such as bed sheets, duct tape and plastic garbage bags that, in the past, could not be dusted with powder. Using a digital camera, a crime scene technician can take a digital photograph of the print. Then Knoerlein uses the software to remove repetitive patterns like the weave of a fabric and make the print more visible.

Using "dodge and burn," Knoerlein can take parts of the image and make the ridges and valleys of a fingerprint appear darker in places where they are too light, or lighter in places where they are too dark. As if by magic, print details appear and can be used by a fingerprint expert to compare against a suspect's prints to see if they match.

Some agencies, including the Broward Sheriff's Office, have guidelines on how the software can be used. Knoerlein says he never uses some of the program tools like the eraser, which he calls "a no-no, because that would be considered an alteration, not an enhancement."

The software has some safeguards to identify if someone tampers with images. But Knoerlein and Erik Berg, who developed the More Hits program, acknowledge that just having procedures on the books is not enough to guarantee the system is not abused.

Like many aspects of law enforcement, it comes down to the integrity of the individuals involved, said Knoerlein. He only enhances the prints that are then sent on to a print examiner, who is qualified to decide if the print matches the suspect.

One of the biggest questions about the new technology is: Could a skillful technician create or copy a suspect's fingerprint and frame someone by making it look like that fingerprint was at a crime scene?

"I don't think I could recreate a fingerprint," said Knoerlein, pointing out that he never sees the suspect's fingerprints. The system might be more vulnerable where print examiners have both sets of prints and also are responsible for enhancing the prints, he said.

"Could it be done? Probably," said Knoerlein. "But it would take a lot of skill and a lot of time."

Berg says a person could be framed if someone in law enforcement took a legitimate fingerprint and claimed to have found it somewhere linked to a suspect.

But it was also possible to do that in the "old-fashioned" system, when police used powder, tape and Super Glue to capture fingerprints.

Technicians did similar things in the darkroom when they used black-and-white film, said Knoerlein. In fact, the term "dodge and burn" comes from the old days of darkroom developing when photographers would use their hands or a piece of paper to cast shadows on parts of a print and expose other areas of it to more light.

That was done under much less controlled circumstances, said Knoerlein. In the computer program, analysts note the changes they make and that documentation is saved with the evidence.

But Reyes' attorney, Heyer, says that's not good enough.

Because the dodge-and-burn process is so subjective -- like sweeping a paintbrush across a canvas -- no technician can exactly replicate the work of another technician, Heyer said.

"There are no proficiency tests, there are no independent studies to say that this works or that it's reliable," Heyer said.

Dr. Jim Ongley, a Broward assistant public defender and former assistant medical examiner, calls it pseudo-science.

"They call it science, but the hallmark of science is the ability to reproduce the same result. If a scientist in Fort Lauderdale and a scientist in California can get the same outcome from the same raw materials, that is science," said Ongley. "This is cosmetic fraud."

Broward Circuit Judge Stanton Kaplan has ruled the evidence can be used in Reyes' trial, so it will be up to a jury to decide whether it can be used to send Reyes to prison for life. If convicted, Reyes will appeal the use of those techniques to Florida's appellate courts.

Prosecutors Deborah Zimet and Tom Kern have other evidence -- the motive appears to be drug-related, the victim's blood was found at Reyes' home and a convicted criminal initially gave a statement that he saw the shooting. That witness, now serving a federal prison sentence, has stopped cooperating with prosecutors. The victim also told his girlfriend during a cell phone call shortly before he died that he was going to Miami with Reyes, an acquaintance, Guzman's girlfriend said.

As forensic experts work to make the system invulnerable to attack, Knoerlein said he hopes that it will soon be standard to have software automatically record everything done to a print. He also wants crime scene technicians to use encrypted cameras that record when an image was captured and whether any alterations were made to it.

In Tacoma, Berg is enthusiastic about the strides made in digital enhancement of prints and how much time it saves law enforcement. It has cut processing time from six hours to 10 minutes, he said.

But in his day-to-day work for the Tacoma Police Department, Berg said he prefers to use the old-fashioned methods unless he's faced with a difficult surface for lifting a print.

"It's like my toolbox got bigger," said Berg. "If I come up with a fingerprint with powder and it's clear -- there's nothing better."