T  H  E      D  E  T  A  I  L

The Detail Archives

Discuss This Issue

Subscribe to The Detail

 

Monday, November 25, 2002

BREAKING NEWz you can UzE...
compiled by Jon Stimac


Fingerprint Update Whittles Suspect Lists - THE FORT WAYNE JOURNAL GAZETTE- Nov. 18, 2002 ...Allen County's AFIS system has helped to double the number of fingerprint identifications...

Search for Killers Leads to Dead End - THE TAIPEI TIMES - Nov. 19, 2002 ...police are having difficulty identifying the two shooting suspect's, even though finger and  palm prints were recovered...

Identification Computerized - THE INTELLIGENCER - Nov. 19, 2002 ...computerized fingerprint databases can quickly match crime scene prints to prints of possible perpetrators...

Fingerprints Lead Police to Burglary Suspect - THE MINNESOTA TIMES - Nov. 21, 2002 ...prints found on a basement window have led to the arrest of a man accused of burglary...

Fingerprint Fuss Talks Debated - THE KNOXVILLE NEWS-SENTINEL - Nov. 23, 2002 ...officials fussing over the costs of fingerprinting criminal suspects...

Break in 1981 Murder - THE MONTREAL GAZETTE - Nov. 23, 2002 ...fingerprints matched by new equipment...
 

Good morning via the "Detail," a weekly e-mail newsletter that greets latent print examiners around the globe every Monday morning. The purpose of the Detail is to help keep you informed of the current state of affairs in the latent print community, to provide an avenue to circulate original fingerprint-related articles, and to announce important events as they happen in our field.

Last week, Josh Bergeron brought us the topic of subjectivity versus opinion. 
For those of you bracing for an awesome detail this week on information, you will have to brace for another week.  It  seems all that information has temporarily incapacitated CLPEX, and I can't even post updated pages to the site!!  I should have the problem worked out by next week, but you may not be able to access portions of the site this week.  

It's actually sort of funny... last week the Detail was by Josh, next week it will be by Glenn, and one of the two cases in this week's Detail was processed by Patrick Warrick. (the bloody palm print on the bed sheet with amido black)  All three gentlemen work for the MInnesota Bureau of Criminal Apprehension!  I would say it's Minnesota month on CLPEX, but we were one week short.  Plus they overlapped November and December.  Sorry, guys... no MN month; but thank you for your contributions!!

The timing for computer problems was OK, though... for those of you who saw 60 minutes last Monday evening, this week's Detail will serve as a continuation.  For the rest of you, this week we look at some of the hot topics regarding digital imaging and fingerprints.
  

We start with a good re-cap of the 60-minutes feature from a news article clipped from the CBS website on Friday, 11-22-02: http://www.cbsnews.com/stories/2002/11/19/60II/main530029.shtml   

********************************************************************

Known as digital fingerprint enhancement, it’s become the silver bullet among police forensic units all across the country, but it was born out of frustration.

The story begins on May 14, 1995 , in Kirkland , Wash. , when police came across a young woman found murdered in her own home. The victim, Dawn Fehring, a 27-year-old bible student and missionary, was found in her bedroom, raped and strangled to death in an apartment virtually sterile of clues.

“It was spotless. I mean, you could still see in the carpet the lines from the vacuum cleaner; there was not a water glass on the counter top,” says James Konat, the prosecutor in charge of the investigation.

Police surmised that Fehring had been baking for Mother’s Day and most likely had left her front door open for ventilation. That explained why there was no sign of forced entry, and they had no witness, no motive, and no hot leads. There was no DNA.

The only real clue they found that day didn’t look promising. It was the victim’s bed sheet, with some bloody smudges on it, like someone had wiped his hands.

“Prior to this time, we were not aware of situation where a fingerprint, or in this case a palm print, had ever been lifted off a fabric, like a bed sheet, particularly a print that had been left in blood,” says Konat.

As every prosecutor knows, you can’t dust a bed sheet for prints. All the distinguishing arches, whorls and loops of a print get lost in the fabric. Technicians tried to find detail on the sheet. They treated it with chemicals, rinsed it, and dried it, hoping for the best. They got detail, but the process also highlighted the weave of the sheet, virtually obscuring the mountain-like ridges of the prints. They called Erik Berg, a forensic expert with the Tacoma police, for help.

Although he worked in the forensic unit, Berg’s real passion was computers. Heavily investing his own time and money, Berg had spent years in the back room of his house developing software that could enhance crime scene photos. He'd been itching to try it on a real murder.

Berg selected what are known as pattern removal filters from his own computer program, which he called More Hits, as well as from Adobe Photoshop, the same software used by artists and many home computer users to fix up photographs and create special effects.

He used his computer to remove the extraneous patterns, and so make the fingerprint more apparent – enough for an expert to make a match.

Once Berg was through, he printed out his work, and handed it back to the examiners, who then checked for anyone considered even a potential suspect who had ever been arrested and had his prints taken. They found one. It was a palm print from Eric Hayden, a 32-year-old mill worker who lived a flight up from Fehring. They used their magnifying glasses and compared Hayden’s print from the files with the enhanced print.

Two hours later, police had made an arrest.

But Berg’s work would mean nothing at trial if he couldn’t prove it didn’t alter the evidence. So, he created what he calls an authentication system to protect the photo’s pixels and track every mouse click and keystroke he executed, so that any expert could repeat the process.

Once jurors watched Berg demonstrate his work, they believed in it. Hayden was convicted and ultimately sentenced to 26 years for the rape and murder of Fehring.

“I really believe that when he left there, he thought he'd gotten away with it,” says Berg.

It didn't take long for cops all around the country to grasp the significance. With this system, cases that were once deemed unsolvable suddenly became hot again. Interest skyrocketed and forensics labs began shelling out more than $40,000 for their own package, including Florida ’s Broward County Sheriff’s office, where Dave Knoerlein has worked with the technology for two years now.

“We’re looking at other cases and looking, re-looking at the evidence in those cases to see if that would benefit from digital enhancement,” he says.

One case involved Victor Reyes, a convicted drug dealer. He was charged with murder in connection with the 1996 execution-style shooting of a man whose body was found dumped by the side of the road, wrapped in a blanket and bound with duct tape. Last year, five years after the killing, Berg's software played a role in identifying smudged prints on the duct tape, originally deemed of no value. The software revealed Reyes prints.

Not everyone likes the new program. “I think this is a prime example of junk science,” says Barbara Heyer, Reyes lawyer. She’s mounting an aggressive attack against digital fingerprint enhancement.

“It's very suspicious that you have something that is of no value and you suddenly enhance it and becomes of value,” she says. “I mean it's very clear that this type of thing can be manipulated.”

Not only did Knoerlein remove the background pattern of the duct tape, as Berg did with the bed sheet, his fiddling went a step further. He boosted the image using a technique called dodge and burn, which uses a computer brush to create highlights and shadows in a picture as photographers do in the darkroom.

Is it an art form, or a science?

“I would say if you're being creative and doing photo as an art form, then, yeah, sure, it could be an art form. As a forensic analyst doing digital image enhancement, I believe it's more of a science, because I'm not-trying to create something. I'm trying to make something that's already there more visible,” says Knoerlein.

The distinction is crucial because unlike removing background, like a fabric pattern - a process that can be tracked and copied - dodging and burning is a different matter altogether. It is as arbitrary as making a brush stroke on a canvass. It can never be done the exact same way again by another forensic expert. And that raises the specter of evidence tampering.

You can’t duplicate the original print exactly, Knoerlein says, but you can get close, and that is good enough.

Heyer disagrees: “When you're talking about someone's liberty, taking someone's liberty away, I don't believe that the courtroom is the place to try out this junk science.”

Berg’s work on the Fehring murder was found to be valid and went on to become part of a landmark case in the state of Washington . Since then, other states have followed, ruling that although new, it is, indeed, a science fit for the courtroom. That includes Florida , where the judge will allow it into the upcoming trial of Reyes. Berg will most likely be called to the stand to defend his invention.

Could the new tool be manipulated to manufacture evidence?

“I think anything man can invent, man can manipulate,” says Berg. “So I’m not going to say, ‘No. It couldn’t be.’ But you still have an authentication process, so if you’re going to do this, it’s going to be a purposeful kind of a manipulation. There’s not going to be, ‘Oh, well, I didn’t know I did that.’ You know you did it.”

In the end, it all comes down to trust.

Says Berg: “I’m not putting your clients’ fingerprint on the evidence and saying,'Look what I found.' Your client put that fingerprint there. I simply found it. Now, did I find it with a magnifying glass? Did I find it with a brush and powder? No. I found it with a computer.”

********************************************************

So what does this mean for latent print examiners?  I am very thankful for "Ski" for agreeing to discuss some of the major implications and attacks we can expect to see (and are seeing) nationwide regarding digital imaging and fingerprints.  Thank you "Ski" for bringing us the heart of this week's Detail...

********************************************

The Hidden Clue Revealed

by David “Ski” Witzke
Vice President, Sales and Marketing
PC Pros


In a recent 60 Minutes II broadcast, the use of digital imaging and image enhancement techniques was featured because this technology is receiving greater acceptance throughout the law enforcement community and is experiencing more challenges in the courtroom. 

In both of the cases highlighted in this feature, the latent prints were identified through the use of digital image enhancements. In one case, the physical evidence was photographed, and in the other case, the image was acquired using a negative film scanner to capture the image from the original negative. 

In both cases, the defense sought to suppress the fingerprint identification on the basis that the methodology of digital capture and digital enhancement of the latent print image was “junk science.” In the latter case, the defense also argued that the subsequent identification made from the original latent print photograph was tainted by the prior identification made from the enhanced digital photograph. More specifically, the challenge went back to how the original image was processed, photographed, and developed as well as how the image was subsequently captured digitally and enhanced to make it identifiable.

Why are allegations of “junk science” and “fabrication of evidence” being used to challenge the digital enhancement of latent prints? Most of these challenges have arisen because of the United States Supreme Court’s rulings in recent years that have imposed more rigorous standards for the admission of “scientific” and expert testimony. 

To debunk the “newness” and “lack of scientific testing” of digital technology in latent print identification, latent print examiners should remember that we have used AFIS technologies for more than 30 years. The AFIS digitizes fingerprints and uses that digitized image (minutiae points) to generate a list of possible suspects. The AFIS technology has been widely accepted and has undergone rigorous accuracy testing around the world.

Digital imaging, whether it be performed on the AFIS or using a digital camera, a film scanner, a flatbed scanner, or a video camera is the same thing. In recent years, we have made tremendous strides with more accurate, more effective, and more affordable technology. As a result, it has been used successfully in numerous law enforcement applications: fingerprints, mug shots, crime scene, domestic violence cases, and so on. Since the technology is receiving such general, wide-spread acceptance, should it be considered new? Or is it really unreliable junk science? Or can we make the point effectively that digital imaging technology is a proven, reliable, scientific tool? What are the challenges that lay ahead in your defense of this technology?

1. The first challenge typically attacks what device you used to capture the image. Defense attorneys have learned that image resolution directly equates to image quality. As a result, they are attacking not only the integrity of the image, but the quality of the image at the point of capture. For example, does the captured image meet the NIST requirements of 1000 PPI for a latent print? But what does that mean? Do you have a device that contains a 1000 pixel capture chip? But what if you are capturing an area that is larger than one inch? Does that affect your resolution? Or if you have a low resolution device, can you interpolate the resolution to achieve 1000 pixels per inch? Or, what format did you use to capture the image? Was it captured as a JPG file or as a TIF or RAW image? Does compression have an effect on the image? Does your digital camera cause aliasing or other artifacts because of color interpolation? 

Many digital cameras only capture one color value per sensor cell (pixel). That value is a grayscale value. Color values are then interpolated for each pixel using the light density of the surrounding photo cell sites based upon the penetration of light through a red, green, or blue filter that is positioned on top of that particular photo cell site. 

For these reasons, defense tries to “imply” that the image was altered at the time of capture, regardless of what device you use. 

2. The next challenge involves what have you have done to maintain the integrity of your digital images. This challenge is often made based upon the opinion in United States versus Jannottie, 673 F.2d 578, 614 (ed Cir. 1982), which stated: “There is no crueler tyranny than that which is exercised under cover of law, and with the colors of justice ….” Many defense attorneys use the statistical role that police and prosecutorial misconduct have played in past convictions. They also allege impropriety and falsification of evidence.

3. The third challenge begins with a question regarding whether the image is an original or a duplicate. In United States v. Beeler, 62 F. Supp. 2d 14 (D. Me. 1999), the Court “viewed both the original and enhanced versions of a surveillance tape … were accurate, authentic, and trustworthy representations of the original tape.” The court further stated “that they depict the same images and have not been manipulated to impermissibly alter the images.”

So where does this challenge lead? The question then arises about whether or not you altered the image during the enhancement process. This is the biggest challenge of all! They get very specific about your enhancement history and how you can "scientifically" repeat your enhancements. OK, so if I have to scientifically recreate the enhanced version, why are “traditional” photographs not challenged? You can enhance your photographs by adjusting the exposure time, dodging and burning, and so forth. So why should digital imaging have such a different standard applied? Typically, the basis for this challenge is that digital imaging is more subjective and less objective. 

The defense also implies wrongdoing by challenging the integrity of the person doing the enhancement..."you made that image match my client’s fingerprints." If you have one person doing the enhancement and another person doing the latent print comparison, this should not be an issue because the person doing the enhancement never saw the matching print and could in no way have altered the image to match the suspect’s prints. Sadly enough, the "implied" intent of fabricating evidence is effective through attorneys leading the witness using the words "alter" or "manipulate." This argument is driven home by showing how magazine publishers “alter” and “manipulate” images every day to increase publication sales. How you articulate your policies and procedures is crucial to the weight of your testimony!

4. Furthermore, the defense took the position that Adobe Photoshop could be used to create fraudulent prints. They fail to make the connection that digital imaging is nothing more than an automation of a manual darkroom process, albeit a more controlled and accurate process than is done in the dark room. Nonetheless, this argument should not be allowed because it has no basis in fact, and the insinuation that it might have been so used is without a factual basis and is highly prejudicial and unwarranted. In Cross v. U.S., 149 F.3d 1190, 1998 WL 255054 (10th Cir. Kan. 1998) the Court stated that the “mere possibility” of tampering was insufficient to prove bad faith. Similarly, in United States v Balzano, 687, F.2d 6, 7-8 (1st Cir. 1982) the Court also approved the trial court’s decision to admit duplicate audiotapes where the defense had alleged that “hypothetically” tampering could have occurred. The fundamental requirement for admitting a photograph into evidence, whether it is digital or film-based, is relevance and authentication. The MORE HITS Forensic Image Tracking System was used to demonstrate the authentication process to the court’s satisfaction. 

5. So what do they have left in their “junk science” argument? The final challenge is to attack the enhancement procedures that you use. The use of “brush” tools, such as dodge and burn, have been scrutinized for their “lack of control” and subjective application. Where precisely did you dodge and burn? Which pixel was altered? As a result, the use of these highly effective tools has become a very sensitive issue. 

In Forensic Digital Imaging and Photography by Herbert L. Blitzer and Jack Jacobia, they state that “only generalized enhancements should be made throughout the entire image….” This guideline precludes the use of tools such as the marquis and lasso tools as well as any "brush" tool. Unfortunately, this “guideline” ignores basic photography techniques that can be performed in the darkroom, including dodge and burn. (Regardless of other positive suggestions contained in this book, the legal community has focused on this one guideline!)

In summary, to help you avoid many of the challenges that are being raised by the defense, you need to remember three key elements: Training! Training! Training! How familiar and/or proficient are you with the technology? How well have you learned to articulate your knowledge in the courtroom? Are you certified as a forensic photographer, a latent print examiner, or a digital imaging technician? Have you ever taken a proficiency test either in photography or in image enhancement procedures? What image enhancement techniques and procedures do you use? Do you have an SOP that regulates and provides guidelines as to what you can or cannot do? For example, does it provide guidelines as to what tools or functions you can use? 

How you answer these questions along with how you address the authentication of your images and how accurately you maintain your image enhancement history are the keys to successfully revealing your hidden clues and receiving acceptance in courtroom.

********************************************

To discuss this week's Detail, visit the informal CLPEX.com message board at
http://www.clpex.com/phpBB/viewforum.php?f=2
As usual, the onin.com forum (http://onin.com/fp/wwwbd/) is also available for more formal latent print-related discussions.

Next week, brace yourself for an awesome Detail by Glenn Langenburg regarding online information! (and hopefully I MEAN it this time!!  it's all up to Topica customer support.  Scary thought.  :)

 

UPDATES on CLPEX.com this week...


No updates this week due to technical difficulties.  Hopefully we will be updated and back online by next Monday.
 

Feel free to pass The Detail along to other examiners.  This is a free service FOR latent print examiners, BY latent print examiners. There are no copyrights on The Detail, and the website is open for all to visit.

If you have not yet signed up to receive the Weekly Detail in YOUR e-mail inbox, go ahead and join the list now so you don't miss out!  (To join this free e-mail newsletter, send a blank e-mail to: theweeklydetail-subscribe@topica.email-publisher.com )  Members may unsubscribe at any time.  If you have difficulties with the sign-up process or have been inadvertently removed from the list, e-mail me personally at kaseywertheim@aol.com and I will work things out.

Until next Monday morning, don't work too hard or too little.

Have a GREAT week!