Sherlock Holmes is known for his ability to notice the tiniest details at the crime scene. He possesses an almost supernatural ability to piece together everything into a coherent picture where other investigators might only see moved furniture or a malfunctioning lamp.
But scientists worldwide are developing technologies that could make even Holmes’s sharp vision more effective, helping him find new evidence that exposes the culprit.
One of the new methods involves the development of software capable of identifying recurring behavior where previously a detective might have relied solely on intuition. Assistance can also come from the emergence of new miniature electronic devices.
Regardless of the field in which the next forensic application emerges, the ability of modern Sherlock Holmeses, as well as law enforcement, to “read” evidence at the crime scene is soon to increase significantly.
Blood Spatter Analysis
Forensic scientists have already learned to determine the direction from which blood spatter originated based on the shape of the stains. However, establishing the height of their source is much more challenging. In 2011, physicists from the University of Washington (USA), experimenting with splattering tomato sauce onto a cinematic clapperboard (a moving board with frame information appearing in front of the camera), devised a method to determine this as well. The clapperboard and the sauce, simulating blood, provided splatter from a specified height. From this, physicists derived a formula that allows for determining the height of the blood source.
Considering the typical velocity at which blood spurts from a wound (determined by blood pressure) and the estimated distance from the wall to the victim, one can make an accurate estimate of the time elapsed before the splatter occurred. From Newton’s laws, we know how such an object as a stream of blood accelerates due to gravity. Knowing the fall time allows for determining the distance the blood traveled and inferring the height of the wound. The height of the wound location can provide important information for understanding the crime scene. For example, could the victim have been sitting when attacked?
Portable Equipment
The miniaturization of devices required by detectives is driven by the same progress that has shrunk computers from room-sized cabinets to pocket-sized gadgets. “Portable equipment is being developed for many fields,” notes Professor Virginia Maxwell of New Haven University (USA). “I am currently working on projects involving portable Raman spectrometers for blood identification at crime scenes.”
Raman spectroscopy allows for determining the nature of a substance by analyzing the scattering of monochromatic light from a laser on its molecules. Different types of molecules — such as blood or some toxic chemical — absorb and emit light at different characteristic frequencies. This has a measurable effect on the incident light.
DNA Analysis
Genetic testing tools are becoming increasingly compact and faster. In February 2011, scientists from the University of California, Berkeley (USA), announced the development of a portable device capable of generating a genetic profile in less than 3 hours (now it takes 8 hours for analysis).
But far more important would be universal DNA sampling at birth. Currently, databases only contain samples from criminals and those who voluntarily provided their DNA during investigations. Universal screening would greatly enhance the potential use of DNA in crime investigation. However, the idea of storing everyone’s genetic profile somewhere would likely provoke societal backlash.
In the future, the quality of collected samples will improve. More information will be extracted from them. DNA phenotyping will enable investigators to determine the appearance of a suspect based on their DNA alone. “In the absence of matches in the database, forensic experts will be able to determine the suspect’s physical traits and behavioral information,” says Professor Jack Ballantyne from the US National Center for Forensic Science in Florida.
Email Analysis
In March 2011, scientists from Concordia University (Canada) published a paper on the study of recognizing characteristic patterns in emails. “Anonymous emails may contain typos or errors, or the entire message may be written in lowercase letters,” says one of the study’s participants, Professor Benjamin Fung. “With a high degree of accuracy, we can determine who wrote it.”
The idea of searching for patterns in text is not new, but Canadian experts conducted a thorough analysis of data and pattern recognition and created a precisely defined and fast-working algorithm that can be used to determine the author of an email. Now, it won’t be the detective who decides whether a threatening email corresponds to other emails from the suspect—the methodology provides evidence that will be more convincing to the jury.
Nanofake parts
Нanofabrication technology, which involves manipulating matter at the atomic and molecular levels, is expected to complicate the interpretation of evidence collected at crime scenes in the future.
Dr. Robert Freitas from the California Institute of Molecular Technology (USA) believes that nanotechnology will make it easy to forge forensic evidence. “Just as a photograph used to be considered undeniable evidence but is no longer, physical evidence can also be easily falsified,” he explains. This could become a major problem for detectives in the future, as some evidence may lose its value.
Determining whether a pipe on the fireplace mantle belongs to the apartment owner or is just a distracting maneuver by the perpetrator trying to throw detectives off track could become challenging. “Traditional physical evidence will no longer be decisive, as molecular technologies can replicate them down to the atoms,” Freitas elaborates. “We may need to rely on other forms of evidence such as lie detectors and total surveillance. It may also be necessary to establish some regulatory restrictions on what can be manufactured on personal nanofabricators.”
Phone examination
The ubiquity of mobile phones and the electronic “paper trails” they leave behind have made them crucial tools in forensic investigations. The mobile network comprises numerous towers with signal repeaters scattered across the country. Each tower serves a specific area, and their coverage zones overlap, forming an interconnected system of hexagonal cells. Mobile companies always know which cell section serves a particular phone. This allows us to accurately determine the location of the phone during a call. Attempts to “hide” by turning off the phone won’t help — when disconnected from the network, it sends a “farewell” signal (unless the location is changed after shutdown). Additionally, mobile phones have other “keys.” They store messages, audio, video, and images, call logs, geolocation data, address books, and calendars. “The amount of information stored on mobile phones will continue to increase,” notes digital forensics expert Andrew Callow.
Electronic nose
Even when the approximate location of a buried body is known, finding it can be challenging. A group of chemists from the University of Leicester (UK) has developed a machine capable of detecting “volatile organic compounds” that arise from the decomposition of biomass. It’s unclear how soon after death gas begins to form, but the scientists from Leicester are “training” their device on deceased animals. Most likely, such electronic noses will play an increasingly important role in airports, helping to detect drugs and explosives.
Statistical analysis
How important are the physical evidence found at the crime scene? The more means of analysis we have, the more crucial such clues become. Therefore, the statistical toolkit provided by Bayes’ theorem for probability calculation will become increasingly valuable. Let’s assume that traces of a rare toxic chemical substance are found on the body using a poison detector. If the detector is accurate to 99%, and the toxin is rare (used in, let’s say, 0.01% of murders), then according to Bayes’ theorem, it will be evident that the probability of poisoning is only 1%, despite the detection of the poison. Most likely, the detector has produced an erroneous result. In other words, 99% accuracy is not sufficient to reliably determine a poison that is used in only 0.01% of cases.
Prints on fabric
A body has been discovered. The probability of finding fingerprints on it is relatively low. However, in 2011, researchers from the University of Abertay in Dundee, Scotland, reported promising results in a study dedicated to obtaining fingerprints from clothing—something that had been elusive in a century of fingerprinting practice.
The new method is based on heating metals in a vacuum (gold and zinc are the most suitable metals based on chemical indicators), resulting in the formation of metal vapor. The vapor is deposited on the fabric and adheres to parts of the clothing that have not come into contact with sweat or oily skin secretions. As a result, we have something akin to a photographic negative—metal is not deposited on the area of the fingerprint. This method, known as Vacuum Metal Deposition (VMD), was invented 30 years ago, but was previously only applied to smooth surfaces such as plastic bags, plastic, and glass.
Currently, only 20% of people are “good donors” leaving fingerprints suitable for detection on fabric. Nonetheless, VMD can show the outlines of a palm print, helping determine whether the person was dragged or pushed. Additionally, fingerprints contain DNA traces, and the results of this analysis will help forensic experts choose the best places to take samples.
Computer murder
The potential for medical implants, such as pacemakers, to become more widespread is undeniable. Dr. Robert Statica, a digital crime specialist from the New Jersey Institute of Technology (USA), believes that these implants will likely be connected to hospitals through a patient’s smartphone. A doctor could then control the pacemaker through this smartphone—a development that could be exploited by particularly malicious criminals.
“If a hacker gains access to this phone, they could change the heart rate frequency of the pacemaker and kill the patient,” explains Statica. Of course, efforts will need to be made to find ways to protect against such attacks and minimize the risk. However, if a hacking attack were to occur, as with other types of computer crimes, there is a chance it could be traced.
All of this is in the not-so-distant future. But what conclusions can be drawn at the scene of an actual crime? Professor David Canter will tell us.
*Professor David Canter is the Director of the International Centre for Investigative Psychology at the University of Huddersfield (United Kingdom) and has been involved in major police investigations.
Identifying Crime Characteristics
One of the key contributions a forensic psychologist can offer to law enforcement is highlighting what stands out at the crime scene. Picture a bedroom with clothes scattered everywhere. There’s blood, but no body. How do you decide what to focus on and what’s most significant? Often asked is when to involve a psychologist in an investigation. My answer: before the crime occurs. It’s essential to gather basic information on criminal behavior that can later inform the investigation. This requires understanding what typically happens in cases such as murder or robbery—typical patterns of behavior. So, we analyzed a vast number of crimes, identifying statistical patterns common to all crimes of a particular type, the characteristics of these crimes. Comparing the details of individual cases with these behavior models allows us to characterize the crime you are currently investigating. Serial killers typically take the murder weapon with them and sexually assault the victim. Killers attacking their loved ones in a single instance do not behave this way. Only specific characteristics of the crime scene will be relevant for analysis. It’s akin to a doctor deciding to focus on high fever and rash, as they are important disease symptoms. Whether the patient suffers from obesity or depression is irrelevant for diagnosis since these traits are common in most middle-aged individuals.
Considering Specifics
In addition to these general characteristics, there are features specific to a particular crime. For example, after analyzing serial killings, four main variations have been identified. In some murders, the victim’s body is mutilated, while in others, the crime scene is ransacked. Sometimes there may be a need to force the victim into sexual activity or evidence of an intention to execute the victim. Certain types of evidence at the crime scene point to these different motives. Scattered items and clothing, for example, indicate a robbery-motivated killing—money may be the motive. Systematic features help indicate to the police what to look for and allow for an initial description of the perpetrator.
Creating a Suspect Profile
After identifying the main characteristics of the perpetrator’s actions, we need to understand who this person might be. This requires a series of “if… then” inferences. For example, if the perpetrator tries not to leave fingerprints or other evidence, can we assume they are an experienced criminal already described in police archives, or are they just careful and have watched a lot of crime shows? The best way to answer these questions is to approach the development of a psychological profile of the perpetrator as solving an equation. On one side of the equation are the “parameters” of the crime, such as time, place, and how it was committed. On the other side are the perpetrator’s characteristics (information about them that is useful to the police). The problem is that human behavior is very complex and influenced by specific circumstances, so there is no simple way to equate the right and left sides of the equation to find the truth.
Nevertheless, we can still gather relatively reliable information about the perpetrator’s character. It could be, for example, impulsiveness or lack of restraint — after all, the crime scene may show that they quickly lose their temper. Or how others perceive them — how attractive are they? All such inferences, like all scientific hypotheses, are partly based on previous research and partly on theories. In the scenario mentioned in the first point (a bedroom with scattered items), the absence of a body is the most striking aspect. This part, related to the parameters of the crime, is more characteristic of a serial killer than a “one-time” criminal. But there are other aspects to consider. How extensive is the disorder at the crime scene? Is there any evidence of a break-in? There are no fantastic logical leaps like Sherlock’s style here. The conclusions are based on extensive preliminary research, and multiple pieces of evidence need to be brought together, rather than relying on individual facts.
Exploring Crime Locations
In the 1986 case of the “Railway R” killer John Duffy, I helped the police focus on a small group of suspects instead of the two thousand on the list. During that investigation, I realized there are two factors that can help link crime scenes to the perpetrator’s base. The first factor is the “proximity” principle: most offenders with more than one offense, at least some of them, commit crimes close to their base (usually where they sleep).
Since then, a common method for calculating the possible location of a perpetrator’s base has been to create a probability area or hot spot map. For each crime in a series, the probability that the perpetrator’s base is located at a particular point is calculated. This calculation is performed for many areas near the crime scene. When these data for all crimes are graphically plotted on a hot spot map, the effect of probability aggregation becomes apparent. Where there is the greatest concentration of points, that’s where the perpetrator’s base may be.
However, there’s a problem — this method is based on the assumption that the connection between the crime scene and the perpetrator’s residence is the same for all types of crimes. It’s assumed that the probability of the perpetrator’s base being located at any chosen point uniformly decreases as you move away from the starting point—regardless of the type of crime. But this is not the case. For example, we know that young offenders don’t move as far as older ones, and that crimes of passion are more likely to occur closer to the perpetrator’s residence than property crimes.
Our current study (results not yet published) fundamentally does not rely on probability data calculated for other types of crimes. We calculate the location of the perpetrator’s base simply by estimating the distances between their actions.
Investigating Crime Scenes
The second key factor is not so much the localization of crimes on the map but the characteristics of these points. For example, how easy it was to see the perpetrator when they committed the crime. This not only determines how far they move away from home but also the direction they choose.
For example, an accomplice distracting attention during a robbery (knocking on the door, pretending to conduct a survey while someone else steals valuables inside) cannot do this constantly in the same area. Then the geographic dispersion of likely locations should increase. Such characteristics can be mathematically modeled, so that the pattern of their location relative to the perpetrator’s base can be traced, helping to find them.
Analyze other evidence
Clues often emerge as a crime is investigated—say, a missing body may be found. This additional information can be included in our equation of activities and their characteristics. When we are trying to identify the characteristics of a criminal based on his actions, the “consistency principle” can come in handy. It states that a person interacts with the world in the same way, unless some external or internal “forces” act on him. This means that the way the criminal acts while committing a crime will not be very different from his actions in other cases.
Let’s look at how the body was left. Was it hidden or left in plain sight? Is it mutilated? Let’s say he tried not to leave any forensic evidence, but the body was mutilated or dismembered. This unusual combination could indicate a very smart but mentally ill person, or someone not so smart but obsessively consistent in their actions.
From an investigative perspective, the most important information is usually provided by the criminal history of the offender. The police have large archives of people arrested and convicted. Consulting these lists is the first step in any investigation of serious crimes, since most of them are committed by people already known to the police. But it is necessary to filter the most likely culprits from all possible suspects, and the equation of actions and their characteristics helps to do this.
Reading the signs of emotions
Information about the suspect’s emotional makeup and interpersonal style may indicate the correct answer. The guys in my group talked to a wide variety of criminals who committed all kinds of crimes – from bank robberies to terrorist attacks.
Our conversations showed that it is most productive to focus on the “personal narratives” that the offender lives by. Let’s say that for him, challenging the police and society is an adventure. Then the victim for him is just an object that he uses, and then simply throws away the body. Fred West, the famous serial killer, cut his victims into pieces to make them easier to bury. He perceived them solely as corpses that needed to be disposed of.
But it also happens the other way around: a criminal can see himself as a victim who must certainly take revenge on certain types of people who have disdained and insulted him in the past. Most often, these are mass murderers who shoot at everyone in a public place.
Studying samples of bodies
Corpse series show patterns that exist in all crimes, as well as variations in patterns over time. If a person’s actions and choice of locations remain virtually unchanged, this indicates a special type of personality – perhaps one with limited resources and psychologically focused on his kills. Any changes, especially when the offender begins to take more risks and moves away from normal targets, indicate that he is becoming more dangerous. At first he may have committed his crimes sporadically, but now they have become a way of life.
Drawing conclusions
When information about a criminal’s characteristics is combined with information about the likely location of his base, the resulting set of information becomes a powerful aid to the police. Thousands of suspects can be reduced to a very small group that requires careful study.
Of course, unlike Sherlock Holmes, we don’t solve crimes through creative insight. In most cases, our contribution to solving a case is less dramatic. Our findings form the basis for training police officers, who, in turn, use them when studying crime scenes. But our help can save time. And life.
