Trooper J.J. Parrish attempts to lift fingerprints from a broken window at the Jefferson High School Ninth Grade Complex in Shenandoah Junction, W.Va., where vandals broke several windows. Photo AP/The Journal, Jason Turner
FEATURED IN INVESTIGATION
Gladys Johnson celebrated her 20th birthday by kneeling down behind a dumpster in a back alley between two bars and shooting heroin into the vein of her left arm. She was up to eight bags a day now, which meant she had to get almost $200 a day just to support her habit. Of course that didn't include the money she had to pay her pimp, so Gladys spent almost every waking moment selling herself on the street.
She had staked out a street corner where she could direct her customers to turn down an adjacent side-street that gave her an unobstructed view in almost every direction. Getting busted by the cops usually meant four or five hours off the street, and she couldn't make any money from the police lockup. By this time, Gladys was pretty street-wise, and although she would perform any act of sex in a customer s car, she was very leery about driving anywhere with a john.
Gladys was still pretty high when the black Cadillac pulled up. She told the driver to pull around the corner, but the man wanted her to get in the car and go to a motel with him. She hesitated, talking with the man through the open side window while glancing around for cops. The john offered $400 for some kinky stuff, but Gladys had done it all, and the combination of her need for money and the heroin she had just taken clouded her judgment.
An hour later, the john strangled Gladys in the bathroom of the hotel. It was the only way he could achieve sexual satisfaction, and he ejaculated in his pants as he strangled her. The man was intelligent, and his favorite television show was CSI. He had read articles about DNA and how the police recovered evidence at crime scenes. So, he took great pains to leave no evidence behind that could link him to the girl or the hotel, always wearing a condom and latex gloves.
A block from the scene, he stopped the car and tossed the latex gloves into a dumpster in a mall parking lot. He was much more careful with the condom and flushed it down the toilet in his apartment.
He should have done more research. If he had, he might have learned of the capabilities of the science of dactyloscopy.
What Is It?
Dactyloscopy is the scientific study of fingerprinting. A fingerprint is the impression of the friction ridges found on the surface of the fingers or thumbs. Fingerprint identification is based upon the distinctive ridge outlines that appear on the bulbs on the inside of the end joints of the fingers and thumbs.1 No two persons have identical fingerprints, making fingerprints the primary method of establishing a person's identity.
Since Francis Galton published his classic textbook Finger Prints in 1852 and Sir Edward Henry developed a system to classify fingerprints in 1897,2 it could be argued that the science of fingerprinting remains the single most important discovery in criminal justice. Only DNA rivals the fingerprint as an absolute method of proving a person s identification.
Most police officers have a basic understanding of fingerprints. Because the Fifth Amendment offers no protection against being forced to submit to fingerprinting, arrested persons are routinely fingerprinted on a fingerprint card or have their prints recorded digitally for transmittal to a variety of state and federal agencies. In 1992, the FBI s Criminal Justice Information Services Division (CJIS) was established and currently has more than 80 million criminal and civil subjects in its fingerprint files.
With the advent of the Automated Fingerprint Identification System (AFIS), prints can be submitted electronically with a turnaround time of hours instead of months. AFIS uses computers to scan and encode fingerprints. It can make fingerprint comparisons and produce a short-list of prints on file that have the closest correlation to the search print(s). (A trained fingerprint expert then makes a final determination on whether there is a match.) The ability to scan an entire database to determine if a latent or patent fingerprint found at a crime scene matches a print on file has revolutionized the art of criminal investigation.
Visible & Latent Fingerprints
Not all fingerprints require the use of developing material. Some are readily visible to the naked eye. Example: If you change the oil in your car, get oil on your fingers and close the car s hood, you may leave visible fingerprints on the hood. These are visible or patent fingerprints.
Shining a flashlight at an angle over a surface sometimes helps bring out the visibility of such prints. Visible prints should be photographed, and whenever possible, the surface on which the prints are visible should be transported to the laboratory.
When a finger touches a surface, perspiration, along with oils that may have been picked up by touching the hairy portions of the body, is transferred onto that surface, leaving an impression of the finger s ridge pattern a fingerprint.3 Prints deposited in this manner are usually invisible to the naked eye and are commonly referred to as latent fingerprints.
Although the vast majority of fingerprints found at crime scenes are smudges and can t be used for identification purposes, fingerprints are such a powerful evidentiary tool we go to great lengths to process the scene for prints. This is one of the many reasons we protect crime scenes from contamination.
What About Gladys Johnson s Killer?
Police searching the area near Gladys murder located the killer s latex gloves among the garbage in the dumpster where the killer dumped them. Jeff Kindle had been a fingerprint evidence technician working for a state laboratory for more than 30 years. He had experimented with trying to develop fingerprints from the inside of latex gloves, but had never had to do so in an actual case. So, when the two detectives brought the latex gloves found in the dumpster to the lab for analysis, he was excited.
He had read several articles detailing the methodology to find and process fingerprints inside latex gloves, including Michael Smith s excellent article Latent Fingerprints on Latex Gloves published by the International Association for Identification.4
It turned out that when the killer had taken off the latex gloves and tossed them in the dumpster, he turned them inside-out. Sometimes the good guys get lucky! Not only was Kindle able to obtain readable fingerprints from the gloves, but the killer s prints were on file with AFIS.
The gloves were found more than a block from the murder scene, so investigators still had a ways to go to link the killer to Gladys Johnson, but eventually they were able to do so. The fingerprints in the gloves led to probable cause and the obtainment of a search warrant. This particular killer liked to take trophies from his victims, and investigators found Gladys panties in the killer s apartment, along with those from other victims.
That's the beauty of science.
1. Gilbert, James A. Criminal Investigation. Prentice Hall, 2004.
2. Saferstein, Richard. Criminalisitcs, 7th edition. Prentice Hall, 2001.
3. Ibid, p. 400.
4. Smith, Michael. Latent Fingerprints on Latex Gloves. International Association for Identification.
Back in the Day
Almost 30 years ago, I was an evidence technician with the Hartford (Conn.) Police Department and routinely processed crime scenes for fingerprints. The department even sent me to a day-long seminar to train me in how to develop latent fingerprints at a crime scene. To make latent prints visible, fingerprint technicians dust for prints using a variety of different colored powders. The color of the powder contrasts with the surface being printed. The powder sticks to the perspiration or oils deposited by the fingers onto a surface.
We often ran out of fingerprints powder back then and used talcum powder and the black powder found in the bottom of copying machines. The department didn't have a fingerprint camera. If a miracle happened and a latent print was developed through use of a powder, we photographed it with a 35mm camera and used regular Scotch tape to lift the print from the surface.
None of us could read fingerprints, so we had to bring any latent impressions to a fingerprint expert at the state lab to determine if the print had sufficient detail to individualize it to a particular person. So, I claim no special expertise in this area of criminal investigation other than to be amazed at how far the science has come since I pretended to be a detective.
The use of chemicals to enhance latent fingerprints was around in my day. We brought paper items to the state lab where they performed iodine fuming, using iodine crystals and exposing them to heat inside a closed chamber to create a vapor that s absorbed by the sweat and oils deposited by fingers to develop any prints on the document. We also used Ninhydrin, spraying it on paper products to bring out the amino acids present in the perspiration on fingers. When we ran out of money we used a variety of hair sprays to try and accomplish the same thing.
Today s fingerprint expert has a variety of techniques available unheard of in my time. Superglue (cyanoacrylate fuming), laser techniques, fluorescents and the ability to find fingerprints on human skin have put the science of fingerprints at a level never imagined even a few years ago.
In the Courts
In 1999, the basis of fingerprint identification was challenged in court in United States v. Byron C. Mitchell. The case challenged whether there is a scientific basis for the individuality of fingerprints. The admissibility of fingerprints identification was upheld in Mitchell.
In 1993, the U.S. Supreme Court case Daubert v. Merrell Dow Pharmaceuticals set the standards for expert testimony. Daubert established the essential factors in scientific testimony, including empirical testing, peer review, error rate and acceptability in the scientific community. All forensic scientists should read Daubert.