As a result of social changes there have been subtle and gradual changes to our skeletal make-ups, making the work of a forensic anthropologist difficult. Those once clearly defined markers on the skull (as well as the rest of the body) are becoming less definitive. It is the responsibility of scientists to grow with the times and expand their arsenal of examination in light of these events.

For many years, it has been posited that the frontal sinus pattern in the human skull is unique to an individual, similar to the idea that fingerprints and DNA are unique. In 2008, a study was published in the Journal of Forensic Science by Roberto Cameriere and colleagues, that sought to test the accuracy of this position. They also sought to measure the rate of false positives between persons that were closely related (kin) to better understand the strengths of using sinus patterns to truly identify human remains.

Cameriere x-rayed skulls of 99 individuals from 20 families between the ages of 15 and 74 (from Northern Ireland). This enabled the scientists to test the effect of closely related persons for false positives. After all the skulls were radiographed and digitally imaged with both anterior (front) and posterior (back) views, they were then statistically analyzed. They used functions and probability to measure the rates of false-positives within their sample.

The results showed that even when examining individuals from the same family group the probability of falsely identifying is very small. They also posited the rate for a false positive did not change significantly when family relation was a factor. This research and its results can be helpful when trying to solve cases [especially with=”” closely=”” related=”” kin=””][/especially] where other heavily relied upon identifying methods (DNA fingerprints, etc.) are inconclusive. These results can provide a level of comfort to the scientist(s) attempting to make identification and serve to improve accuracy in tough cases.

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The system worked quite well, until 1903 when Will West was received at Leavenworth Penitentiary. Upon running Will West’s measurements, it was discovered that a “William West” was already imprisoned at Leavenworth.  He had the same anthropometric measurements as Will West.  A photographic comparison of the two men did little to distinguish them.   Finally, two years after Will West was brought to Leavenworth, fingerprints of each man were taken, compared, and found to bear no resemblance.  Thus each man was distinguished by his fingerprints.  Needless to say, Leavenworth converted from the Bertillon system to the more reliable fingerprint system, which is still in use today. This is a reminder that fingerprints are important.

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Both New York and Maryland have computerized ballistic fingerprint databases, both states have legal mandates that require all firearms manufacturers to provide, a spent cartridge and prepare ballistics images of the bullets and cartridge casings and provide the records so that the state’s law-enforcement agencies can access it, for every firearm legally sold; the law also requires that the name, address and Social Security number of the person purchasing the firearm be linked to the ballistics information.

The law, and the database, is based on the theory that that every gun marks shells and bullets in specific, stable, identifiable ways.  The reason casings are used is because firearm that produce marks on cartridge cases are less subject to long-term wear.  This theory, unfortunately, has not been scientifically proven.  In fact, the markings left by a gun on a casing are not guaranteed to be the same over the long term and can be deliberately changed with simple tools such as a file or metal brush.

Another problem with the ballistic fingerprint database, as it stands, is that only new gun purchases are beholden to the law, meaning that the millions of already purchased guns cannot be traced via the database.  Other concerns include the fact that less than 1% of legally guns sold will ever be used in a crime, guaranteeing wasted effort.  Beyond that, nearly 90% of guns used in crimes change hands at least once after their initial purchase at a licensed dealer before being used in crimes; it has been estimated that nearly 40% of guns used by criminals are either stolen from their rightful owners or purchased on the black market.

There is also fault with the potential usefulness of such a database.  California did some extensive testing to assess the accuracy of such a database and they found that when shell casings used with a particular gun came from the same manufacturer the computer failed to match the correct casing to its gun 38% of the time; when casings came from different manufacturers the failure rate was 62%.  These false matches waste the time of ballistic examiners who are left ruling out matches made by the computer database. New York has had its database up and running since 2002 and has since entered data from over 200,000 new gun purchases and has spent approximately $1,000,000 a year on its system. By 2007 the system had not led to a single solved crime.

Fingerprint and DNA databases see their success from the fact that neither identifier is subject to change, a person is stuck with the DNA and fingerprints they are born with, but this is not the same for a gun and its parts. The parts of the gun that are responsible for marking a shell casing are the breech face, extractor, ejector, and firing pin, all of which can be purposefully altered with specific tools or all of which may change with time and normal wear.  Although the idea of a ballistic database is appealing given the large amount of gun violence in the US, unfortunately the ease with which guns can be altered appears to throw a monkey wrench in the idea.

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Is bacteria the new forensic tool

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Sherlock Holmes worked as a consulting detective in London with his partner Dr. John H. Watson, who moved in with Holmes to help pay the rent.  Holmes was a freelance detective as well as a forensic scientist, the first of his time.  Holmes is unlike anybody we would find working in forensics today because of his disciplinary crossing reach.

Holmes worked as a detective and as such used his sharp mind to “reason backwards” or to see the conclusion of a criminal act and be able to reason backwards to find the motive and the culprit.  But Holmes was much more than just a detective.

Sherlock Holmes also worked in the chemistry lab of a hospital, making him a forensic chemist.  Holmes “discovered” a test to detect hemoglobin, and hence blood, he did this in Doyle’s mind 13 years before it happened in the real world.  Holmes commented on the uniqueness of typewriters three years before any real life document examiners did the same. He is considered a pioneer in the use of forensic science.

Today forensic chemists do not do detective work in the field and detectives do not spend time in the laboratory examining evidence, these are two separate arms of law enforcement.  Sherlock Holmes was a genius at both as best described by Doyle’s quote from Holmes’ mouth expressing both processes in one eloquent statement:

“The process… starts upon the supposition that when you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth. It may be that several explanations remain, in which case one tries test after test until one or other of them has a convincing amount of support”

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The driving force of art forgery is the fact that art work created by certain artists is worth more than art work created by others.  If a work of art can be replicated perfectly by an art forger it is only worth less monetarily than the original because of who painted it not because the painting looks any differently than the original.  The same theory applies to forgers who create new art pieces in the style of a master, if the forgery is believed to be genuine it will be deemed priceless but if it is found to be a fake it is deemed worthless, regardless of what the piece of art looks like.

Forensic investigators, along with art historians and appraisers, are often responsible for determining if a piece of art is a forgery or not. Historians often use stylistic analysis to determine if a work of art is genuine or not, possessing large amount of knowledge about the styles, tool, brushstrokes,  techniques used by certain artists. There are a variety of methods used for forensic authentication of art work.   Some of the technical methods for revealing fakes include X-rays, UV lights, and IR light, which can be used to see under layers of paint to see covered up works, determine time period or the actual artist of the painting if an original signature has been covered up.  Chemical analysis and spectral comparisons can detect the components of paint to ensure that modern pigments were not used in supposedly old paintings.  Examination of the craquelure, the network of cracks that appear on old paintings, can be analyzed to ensure that the cracks were not artificially made and that they follow the grain of the wood onto which they were painted.

Art forgery sounds like a thing of the past, but art dealers claim that about 15% of art sold at auctions are fake, which means hundreds of people getting conned out of thousands of dollars.

For more information on art crimes  save the date, the Museum’s new art crimes temporary exhibit is coming on February 15th, 2010!

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Fingerprint residue contains natural salt secretions that corrode metals at the points where the salt contacts the metal. This microscopic fingerprint corrosion leaves a permanent mark on metal that cannot be washed away. The heat of the firing of the gun also does not alter these marks.

The new technique that has been established to visualize these types of prints relies on running electrical current over the metal object , such as a bullet casing or a gun, that has been coated with a fine toner like powder. When a charge is run down the metal object the fine conducting powder is attracted to these areas of corrosion revealing a powdered fingerprint.

This technology can also be used in fires to recover prints of metals exposed to very high temperatures.

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Now a public figure, Dillinger turned to plastic surgery to alter his identity and evade Purvis and the rest of the law enforcement community. In those days, plastic surgery was not as common as it is today, and the medical procedures were primitive, dangerous, time-consuming and very painful. Dillinger underwent several bouts of plastic surgery, some more successful than others, but in the end he only managed to slightly alter his appearance. After one round of plastic surgery from which he was extremely disappointed to find that he still looked the same, one of the doctors suggested that he remove his fingerprints as a way to escape being detected. Dillinger liked this idea and elected to undergo the painful process of obliterating his fingerprints.

A wanted poster for Dillinger, complete with all ten fingerprints

Dillinger was not the first criminal to come up with that idea. In 1933, “Handsome Jack” Klutas had attempted to file down the small ridges on his fingers, but he ultimately failed. Two of Kate “Ma” Barker’s clan, Alvin “Creepy” Karpis and Ma’s son Freddy, decided to remove their fingerprints as well, so they hired mob physician Joseph P. Moran to do the job. Moran was inexperienced in this procedure and repeatedly hacked and knifed at their prints until the gangsters couldn’t bear any more pain, but when their fingers finally healed, the fingerprint ridges grew back to their original patterns.

Hoover was aware of this trend among criminals and he became wary of the possibility of success. He commissioned several surgeons and dermatologists to report on the likelihood of someone obliterating their fingerprints, and in 1934 they came back with their findings. Dr. Howard L. Updegraff, a member of that committee, had extensive experience in the area of fingerprint alterations and he reported that the only way to permanently obliterate a fingerprint is to graft skin from another part of the body over them. And in 1941, that’s exactly what Robert Phillips did when he got a doctor to graft the skin from his chest on to the tips of his fingers. Phillips, however, was caught because the ridges surrounding the graft areas, as well as on the other joints of his fingers were used to identify him.

Dillinger seemed to have taken the road less traveled when he chose acid to burn the tips of his fingers with in late May, 1934. The procedure appeared to be successful; however, faint ridge markings were still visible on his fingertips after the full healing process, as were seen after Dillinger’s death.

Many people in American history have attempted to elude the authorities by scarring or ruining their fingerprints, but forensics has been able to keep up with those criminals all the while. In fact, as Phillips found out firsthand, just ruining the tips of one’s fingers does not preclude fingerprint identification. The ridges that are found on the tips of one’s fingers are also found on the entire surface of the palm, and they are just as unique to an individual. Furthermore, by introducing scars onto one’s fingers, it makes the identification process even easier, since the scar patterns are unique and less common to the general population.

If one thing can be learned from Dillinger and the other notorious outlaws of the Gangster Era it’s that crime does not pay, and eventually criminals will be brought to justice, and not always the pretty way.

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When light is shined on a surface, the surface can either absorb, reflect, or transmit the light. In special situations, the light that is shined on an object is absorbed by that material and then re-emitted at a different wavelength (called a Stoke’s shift), which is known as fluorescence. Typically when an object fluoresces, the light is re-emitted at a lower energy state, and therefore, at a longer wavelength. In the case of blue light as the incident light, the re-emitted fluorescence usually occurs in the orange spectrum – that’s why investigators wear orange goggles! In order to see the faint fluorescence, investigators must block out all the blue light from entering their eyes since that would drown out the faint fluorescence, so orange goggles will only allow orange light to reach their eyes, and hence, the fluorescence is observed.

Many body fluids, organic materials and fibers will fluoresce under the forensic light source, and other materials such as blood, gunshot residue, and some inks will absorb blue light to appear dark under the light source. These substances are often not observable to the naked eye, and especially if the surface was wiped down or cleaned. The forensic light source is always a good starting point in a crime scene search because it is portable, quick, cheap (once the unit has been paid off), and most of all, non-destructive, meaning that it will not damage or harm any of the evidence.

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does occur, it draws huge attention and everyone wants to get involved in the case. Homicide investigations rely on a large amount of teamwork and draw upon many sources of information, and forensic evidence is only one component of it. Let’s take a brief look at the 5 defining characteristics of a homicide and how they are essential in helping investigators understand their crime and apprehend their criminal. These characteristics were developed and defined in the FBI’s Crime Classification Manual, Second Edition, whose goal was to standardize terminology, facilitate communication within the criminal justice field, educate the criminal justice system and public about the types of crimes being committed, and develop a database for investigative research.

1. Victimology

What makes homicides unique from property and non-violent crimes is the fact that there is a victim. The victim is very often the most important investigative tool, since a lot of information can be revealed about the case from studying the victim. If investigators can answer the question why the victim was targeted, then they are often lead to the motive and potentially their offender.  Areas of the victim’s lifestyle, habits, relationships, employment, personality, leisure activities, alcohol/drug abuse, dating habits, etc. are excellent sources of information about what increased the victim’s risk.

2. Crime Scene Indicators

The location, environment, and time of day may present significant clues as to the nature of the perpetrator and the amount of risk he is willing to take and shed light on the motive of the criminal. It is also possible for there to be several crime scenes as well, such as if the victim was transported at some point during the crime, and that may tell investigators how organized the criminal is. The disposition of the body at the crime scene, if it was concealed, displayed, or positioned may also tell investigators a lot about the criminal and if there was a message sent by the murder. Furthermore, items are often left at the scene, such as a weapon, or removed from the scene, such as a souvenir, which can narrow down the type of criminal, and restraints or other tools of the crime left at the scene can potentially paint a better picture of the crime.

3. Staging

This is the purposeful alteration of the crime scene, meant to mislead investigators. Inconsistencies in the crime scene often uncover staging attempts.

4. Forensic Findings

The value of physical evidence at the crime scene is well known and can be crucial to any homicide investigation. The cause of death, types of trauma, indications of sexual assault, toxicology reports, and hair/DNA/fingerprint/etc. analysis can all lead to apprehending the criminal.

5. Investigative Considerations

These considerations are usually taken once the homicide has been classified, and may include search warrants, locating and interviewing witnesses, and documenting the crime scene.

By using these defining characteristics as a starting point, investigators are usually able to gather a lot of information that will help them in the case. They also generate profiles of criminals to help them determine motive and opportunity. Finally, the information that they gather may help investigators link different crimes based on similar MO’s or criminal signatures, and may be the key to breaking other cases.

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