If you'll recall my last installment, in this, my ongoing series of articles about visual tracking, I shared the story of an accomplished tracker differentiating between the boot prints of two different suspects. He'd noted and articulated several seemingly innocuous differences, despite the impression evidence being left by seemingly identical boots worn by two physically similar men - same boot size, same approximate height, same approximate weight.
When it comes to suspect identification, footwear impression evidence (as much as other facets of tracking) is just as easily articulated, just as admissible, as other forensic evidence and it should be utilized far more frequently by law enforcement than it currently is. For similar reasons, with different applications, it is likewise underused or misunderstood by the military. Think about it now: you can wear a ski mask or spraypaint video camera to hide your features; wear a pair of gloves or coat your fingertips with superglue to hide your fingerprints; even shave yourself and wear a condom to avoid DNA evidence, but unless you can levitate or get yourself miracled into a crime scene, you have to walk in and out. You can detonate an IED with a cell phone or wire or a timer, but absent superb mastery of telekinesis, there's only one way to put it in place.
So, regarding identification, how do we identify a particular individual or tell multiple subjects apart? The first thing is to be aware that it can be done and to develop a habit of looking at the details. Sometimes this is possible based upon experience and interpretation. Others might require sketches or photographs. However we note and record the individual characteristics, it will require some form of comparative examination and the ability to explain why the details mean what the tracker says they mean (which is no different as far as that goes from other aspects of police work).
There are three basic areas I use to categorize the particulars I find in a print. These may not be the same as those a forensic podiatrist might use, but in the end that's semantics. For official terminology, you'd do well to consult an expert like Bodziak. Note that these are print differences. There will be others in the track line, differences in stride length and pitch angle, but in the print itself you can largely define differences as permanent (or class) characteristics, temporary characteristics, and particular (or individual) characteristics.
The best part about these characteristics is that they're largely interpretive right there at the scene. Unlike fingerprints or DNA, you don't have to send them off to a lab, conduct a reaction test or any kind of chemical analysis.
Permanent characteristics are going to be dependent upon the style of boot and manufacturer. Think in terms of being able to recognize and contrast tread patterns, such as the distinct sole of a specific breed of Reeboks vs. those on the bottom of a pair of Adidas. They may appear to be similar at a glance, but any close examination will discern loops and whorls, checks or stripes or Vs, even the brand name (you would be surprised to see how easily the word REEBOK or DANNER can be read in soft soil or the right textured sand). There will be differences between styles within a manufacturer's product line and sometimes differences with a certain style from one year to the next. All aspects of the sole pattern produced on the assembly line are permanent characteristics.
Temporary characteristics are transient, and may change as the wearer travels. Mud caked in the grooves of the heel will produce a distinctive print until it is knocked loose or washed off, an adhesive-backed plastic label stuck to the ball of a foot will change the pattern until it peels or falls off, etc. Temporary characteristics, as the name implies, cannot be relied upon to be consistent but may prove to be of good evidentiary value if properly interpreted (think red clay from southern Oklahoma stuck in the tread of a hiker's boot, altering the tread pattern before ultimately being deposited in a print found in the black soil of southwest Missouri). This may have implications far beyond suspect identification - savvy border trackers in Israel, for instance, are well aware of the differences between the respective soils of the Negev and Sinai Deserts, and those of the Beit Shean Valley vs. the Beka'a Valley, and use that knowledge to track and identify infiltrators and smugglers all over the country.
Individual characteristics may be of the greatest importance to a criminal investigator. They may be accidental, such as a gouge carved from the heel of a work boot by a piece of rebar on a work site, or intentional, such as the cuts placed into the soles of convict boots intentionally by some prisons and detention facilities. In the latter case, these marks are often unique to a specific cell block or ward. Other individual characteristics (and by far the most common ones that I've seen) are those created by the wearer. These are often the result of different walking styles or gait, the length of time worn and the environment they were worn in and even physical injury or impairment. The soles of a pair of shoes worn every day on the sidewalks of New York by the guy that had his ACL replaced twice are probably going to look different than those of the guy that broke his left ankle last year.
Another thing to keep in mind when doing a comparative analysis is that wear patterns from the same individual will typically be consistent. You're going to wear this pair of shoes largely the same as that pair of shoes. Anthropologist Louise Robbins wrote, "By the time we reach adulthood it [individual footprints and gait] is very much a part of us. Even if you had a twin you would not walk the same way... You can look at the other shoes of the suspect, and... if he is involved, you'll find exactly the same wear pattern on all his shoes."
That's handy eh?
Whatever the tracker's skill level, even being what trackers call track aware will make it more likely that footwear evidence is noticed and used. Much of what I've described may sound like voodoo or something out of a Peckinpah movie, but really it's just a matter of honing your powers of perception and taking note of the details once you know what to look for. The average patrol officer doesn't have to be a Mike Hull, David Diaz, Amos Yarkoni or Mel Odom to use visual tracking in the investigation of a crime. He just needs to open his eyes and pay attention (though learning form guys like that can certainly help).
Now, before I wrap this up, let me say a word about training - like everything else, keep an open mind when you seek out training and always be looking for something else to learn. Though there aren't nearly as tracking instructors out there as there are for other tactical disciplines, even they don't do everything the same, and many have their own ideologies. David Scott-Donelan's cadre with the Tactical Tracking Operations School teach a lot of team-oriented techniques to go along with the individual's skill set, and set high standards of physical fitness, situational awareness and tactical proficiency due to their audience (they currently hold the sole-source tracking contract for DoD and JSOC, and teach many law enforcement classes as well). Joel Hardin is widely respected as an accomplished tracker and tracking instructor, but he openly disdains the term tactical tracking, disputing the need for tactical considerations on a follow-up and openly mocking instructors from other schools of thought. Kevin Reeves has successfully taught tracking for several years with On Point, with instruction that has been well received by military and police students alike, but his actual operational experience is minimal. Finally, the well-published and widely known Tom Brown has taught hundreds if not thousands of students over the years and even provided technical advice to Hollywood productions, but his courses are expensive (particularly from a cop or soldier's budget) and very focused on what might called holistic or existential skills. By many accounts his methods work, but a police detective would be well advised to think long and hard about how he intends to testify on the stand about what he was able to glean at a crime scene by dint of his totem or the spirit of the track.
Let me be clear - each of the men mentioned above is a tracker of proven skill and established reputation. Newcomers to the art and science of tracking would do well to perform due diligence when considering where to go learn. I'm not one to utterly reject any training out of hand without looking into it, and frankly, the fact that I've taken a class from, say, Jim Cirillo in no way prevents me from also wanting to seek the tutelage of Ken Hackathorn or Glenn Langley.
I'd teach you myself, but my stride length is so short you'd have no problem at all closing the time-distance gap... so I'll just continue to pontificate.
