how (not) to murder your wife

Whew! I am back briefly in Washington DC after a 10-day trip to three different cities, and a whole lotta blogging in between. Thanks, as always, to Lee Kottner for ably filling in for me here at Cocktail Party Physics with excellent posts on Hubble, a space elevator update, and manned missions to Mars. And a warm, heartfelt thanks to everyone who commented, linked, etc. to offer well wishes and congratulations on my forthcoming change in marital status. After less than a year into my bloggy existence, it really made me feel part of the growing science blogging community -- although Jen-Luc Piquant rather snidely points out that the only post dealing exclusively with my personal life generated more hits and links than anything I've written about science. Being of a pretentious bent, she's dubbed our combined public persona "Seannifer," a la Brangelina and TomKat. (According to this rating system, Sean is an A-List blogger, whereas I am a B-list blogger. Cynical sorts might say that I am carrying on the Katie Holmes tradition of "marrying up" -- in this case, to promote my standing in the blogosphere. Pfft, I say. What's a Technorati ranking, anyway?)

Shiny new A-list fiances notwithstanding, the marital state is not without its perils, even if one's (future) spouse happens to be a physicist. Yesterday I stumbled across an article about a University of Alabama, Huntsville, physics professor who has been arrested for murdering his wife. Forty-five-year-old Andrew Pakhomov allegedly -- remember, innocent until proven guilty, people! -- strangled his 42-year-old wife, Yelena Zakin, with a braided brown leather belt and dumped her body in the Tennessee River after weighting it down with a bag of rocks.

The motive for the murder is murky. (The folks at Beatrice somewhat cynically point out that Pakhomov has a book coming out next August on the physics of plasma dynamics and ablative laser propulsion. However, we are doubtful that being accused of murder will substantially boost the sales figures for a highly technical reference book.) There was a history of domestic abuse in the marriage, a possible extramarital affair, and Zakin herself was arrested shortly before she disappeared, for assaulting her husband in the university's optics building when she found him in his office with a female colleague. Pakhomov's stepdaughter is on record saying that the couple's marital problems began when the physicist failed in his bid to chair the physics department.

It is, ultimately, a tragic tale, one that has rocked an otherwise peaceful academic community.  Pakhomov is currently out on bail, awaiting trial, and his lawyer maintains his client's innocence. Details regarding hard evidence in the case are sketchy, but police apparently found unspecified "forensic evidence" in Pakhomov's SUV, and the belt used to strangle Zakin was very similar to the one Pakhomov was wearing at the time of his arrest. The latter is decidedly circumstantial evidence; in general, prosecutors of homicide cases prefer more solid, scientific evidence: DNA samples, for example, or clearly identifiable fingerprints. (Yes, we watch C.S.I. And Law and Order. And even Bones, when time permits.)

Fingerprinting as a means of personal identification has a particularly long and colorful history. There is evidence that ancient Babylonians used fingerprints on clay tablets to ratify business transactions, while in China, thumb prints have been found pressed into clay seals. Persian official documents in the 14th century relied on fingerprint impressions, and one official noted that no two prints seemed to be identical. In 1686, an Italian professor of anatomy in Bologna named Marcello Malpighi noticed there were distinct ridges, spirals and loops in fingerprints, but it never occurred to him that these patterns might be unique to individuals, and therefore might be a good tool for identification. (The "malpighi" layer of skin was named after him, however.) A century and a half later, in 1823, another anatomist named John Evangelist Purkinje (of the University of Breslau) published a thesis detailing nine distinct fingerprint patters, but again failed to recognize their value as a useful identification method.

It was a 19th century English Chief Magistrate of the Hooghly district in Jungipoor, India, who unwittingly revived the ancient tradition of using fingerprints to "ratify"   contracts with the local natives in July 1858. At first, Sir William Herschel didn't intend anything more than to frighten a local businessman named Rajyadhar Konai so that the latter wouldn't be tempted to renege on the terms of their agreement, but the practice was so effective, Herschel soon required palm prints (and later the prints of the just the right index and middle fingers) on all contracts made with the locals. Apparently, they believed the personal contact with the document was magically more binding than a simple signature.

That was pretty much the extent of Herschel's contribution to fingerprinting, but he did notice that his inked prints could potentially be used for identification purposes. In 1880, Dr. Henry Faulds published an article in Nature about using fingerprints to establish identity, as well as using printer's ink to make print impressions. Faulds is usually credited with the first fingerprint identification, by analyzing the greasy fingerprint on a discarded bottle of alcohol. (It didn't take long for the practice to worm its way into literature. Mark Twain's Life on the Mississippi depicts a murderer being identified by his fingerprints, while in a later novel, Pudd'n Head Wilson, the central court trial rests on fingerprint identification.)

An Argentine police officer named Juan Vucetich made the first criminal fingerprint identification in 1892. Francisca Rojas murdered her two sons, then cut her own throat in a lame attempt to deflect blame on an unknown attacker. But she was sloppy, and left a bloody print on a door post, and Vucetich was able to prove she was the murderer based on the arches, loops, and whorls that made up her unique print pattern. Since then, the field has flourished and become a vital component of the criminal justice system. Today, the FBI maintains a database of more than 49 million digitized individual fingerprints called IAFIS.

As any diehard fan of crime shows would know, conventional methods for lifting fingerprints at a crime scene involve treating the samples with powders, liquids or vapors to add color to the print to enhance the contrast so it can be easily seen and/or photographed. However, some of the chemicals used to collect fingerprints can actually alter, contaminate or destroy them, particularly when lifting prints from unusual (e.g., highly porous) surfaces, such as fibrous papers, textiles, wood, leather, plastic, or even human skin. They can also damage other valuable forensic evidence like blood or saliva. Furthermore, chemical based methods can take hours or even days to process if the print needs any kind of contrast enhancement. (In one memorable C.S.I. episode, Grissom discovers that a previously hidden fingerprint on a matchbook "develops" over several months after being sealed in an evidence bag.)

Wouldn't it be great if crime scene investigators had a method for collecting print samples while leaving the print intact? There may be hope for Grissoms of the future. Scientists at Los Alamos National Laboratory have developed a new fingerprint visualization technique using X-rays that not only leaves prints intact, but can also reveal key chemical markers, thereby providing new clues for tracking criminals and missing persons. Chris Worley is an analytical chemist with the lab, who conducted the preliminary studies last year of the new technique to test its viability. It's called micro-X-ray fluorescence (MXRF), since it uses a thin beam of X-rays to irradiate a sample to reveal its elemental composition.

Scientists have long known that chemicals give off distinct "signatures," emitting or absorbing radiation at very specific wavelengths. Sodium, for instance, which is used in street lights, gives off primarily orange light, while the oxygen used in neon lights emits mostly green light. This effect is the basis for most spectroscopy techniques, which in turn enable astronomers to ascertain the chemical composition of distant celestial objects, for example. Pass light from a star through a spectrograph, and it will spread into an electromagnetic spectrum, much like visible light breaks into its component colors when it passes through a glass prism. Astronomers can then analyze how the spectrum becomes brighter or darker at each wavelength and determine which chemicals are present in the source star.

That same principle applies to earth-bound spectroscopic applications. For forensic fingerprinting purposes, salts such as sodium chloride and potassium -- commonly secreted in human sweat -- are of particular interest. Worley's group showed that the MXRF method can detect the presence of such salts (assuming they are present in sufficient quantities), and since those salts are deposited along the patterns in a print, it's fairly easy to produce an elemental image of that print for analysis. According to Worley, the method is especially promising for imaging children's fingerprints, which are more difficult to detect than adult's.

Worley and his Los Alamos colleagues aren't the only scientists grappling with the print preservation problem. Optics researchers at the University of Pennsylvania have devised their own light-based method for recording fingerprints without using chemicals or otherwise disturbing the delicate latent prints at a crime scene. Their method doesn't require X-rays, or much in the way of specialized equipment; just a standard light source, a polarizing filter -- similar to the ones found in higher-end sunglass lenses -- a digital camera, and a computer to process the collected data. You just need to shine the light on the fingerprint at a certain angle and position the polarizing filter in such a way that reflected light passes through it. The filter will then selectively darken either the background or just the outlines of the fingerprint. This increases the contrast, such that the print is more clearly visible against the background surface, so it is visible to the eye or the lens of a digital camera. There's a patent pending on the technique, and the scientists are now building a prototype portable version of the system.

So fingerprinting just gets better and better. Add DNA evidence to the mix, and it's pretty tough to get away with murder these days -- or even prankish Cyber-crime. For instance, Jen-Luc purportedly spent a wild weekend carousing in the virtual world Second Life, but the festivities were cut short by a marauding army of self-replicating virtual gold rings that overloaded the servers. I'm not accusing her of being directly responsible for this "grey goo" Cyber-scenario, but she has been known to use the CopyBot program -- a practice that hard-core Second Life users frown upon -- which performs a similar function. Where there's smoke, there's sometimes fire. Jen-Luc's virtual fingerprints could be all over this case....

Comments

[Jenn]

This is why I enjoy this blog: from marrage to murder to fingerprints to x-ray spectroscopy. I know I've never seen all of those in the same place before.

[TBB]

Maybe Pakhomov is innocent, or he's not a very creative phyicist. Strangling by belt is rather pedestrian, don't you think? Death by laser would have been more in tune with his research.

(Not to make light of a death, for the morbidly humorless.)

[TBB]

That would be physicist...of course!

[Blake Stacey]

A significant early use of fingerprinting in crime fiction is Sir Arthur Conan Doyle's "The Adventure of the Norwood Builder" (1903). It fits nicely with our modern expectations of twists and turns because -- SPOILER ALERT -- Sherlock Holmes realizes that the supposedly damning fingerprint is in fact a clever forgery.

http://en.wikisource.org/wiki/The_Adventure_of_the_Norwood_Builder

And as for the Pakhomov case. . . it is always nice to see one's hometown and one's profession make the headlines. :-/

[TBB]

Huntsville: murder, bus accident... Blake, your hometown sure isn't getting great news lately. But Huntsville *does* have that Saturn V standing up there like a church steeple from a distance - a beacon. That must be cool.

The Finger Prints for Dummies site Jennifer posted has some good FAQ:
http://www.onin.com/fp/lpfaq.html#q2jq

[Lab Lemming]

I should get more interested in fingerprints in my lab. There are certain scientists who both fail to wear gloves and clumsily handle the standards in a way that leaves huge, greasy stripes across their faces. It only recently occurred to me that these stripes may contain personally identifiable information that may let me determine the culprit...