The Perfect Murder

Is modern forensic technology making it impossible
for someone to get away with murder?

Zak Martin



Crime fiction writers give their criminals far too much credit for class and intelligence. The reason is obvious. In order for a story to have tension, the hero has to be up against an adversary who is worthy of his or her crime-fighting and detection skills. Ideally, the bad guy should be a criminal mastermind – fiendishly clever, dangerous and resourceful. After all, there wouldn’t be much of a story if the baddie was an idiot who made enough mistakes and left enough clues to get caught in the first chapter.

In reality, most criminals – or at least most of the criminals who end up in the dock – are not very bright. In many cases they turn to crime precisely because they lack the necessary intellectual wherewithal and self-discipline to make a living by legitimate means. Around 50% of convicted criminals reoffend within a year of being released from prison. Or, to be more precise, around 50% are caught reoffending, which tells us as much about their intelligence as it does about their morals. Not surprisingly, then, most crimes are messy and either unplanned or badly planned. This is particularly true of murders. A junkie desperate for money to buy drugs holds up a liquor store and ends up shooting the owner. A married couple have a quarrel which escalates until one of the pair picks up a kitchen knife and stabs the other to death. A man gets into a fight with his neighbour over a TV set that’s too loud, and, in a fit of rage, one of them batters the other to death with a baseball bat.

Most murders are sordid and unpremeditated, and it doesn’t require great powers of detection to figure out what happened or who was responsible. They are, in legal jargon, open and shut cases. Invariably, the only argument is over the degree of intent.

People who commit unplanned murders (second degree murder, in the United States, or in some cases voluntary manslaughter) often try to conceal the evidence of their crime by dumping the body in a place where they think it won’t be discovered, getting rid of the murder weapon, and cleaning up blood stains and other incriminating evidence. Almost invariably they are wasting their time. Bodies have an uncanny knack of turning up, no matter how carefully they have been hidden; and with the array of sophisticated forensic techniques and resources investigators now have at their disposal – fingerprint analysis, DNA analysis, fibre analysis, vibrational spectroscopy, CCTV, sniffer dogs and so on – most impromptu killers might as well leave their business card at the scene of their crime.



Body recovery
The bodies of murder victims, however carefully disposed of, have an uncanny knack of reappearing.

Premeditated murders are less common; and the kind of ingenious, carefully-planned murders you read about in detective novels or see on TV – murders that can only be solved by super sleuths like Columbo or Hercule Poirot – are, it would seem, extremely rare.

But are they?

The thing is, we don’t really know how rare clever murders are, because if they were clever enough to go undetected, no one would know about them to begin with. The “perfect murder”, if there is such a thing, is not a murder which goes unsolved. Rather, it is a murder which is never suspected in the first place. When carefully-planned murders come to light, it is often as a result of luck rather than brilliant detective work. We can only guess how many people who were believed to have died of natural causes or in accidents were actually done away with by people clever enough to conceal their crime.

Until fairly recently the only thing a person intent on murderer really had to worry about was leaving their fingerprints at the scene, and that risk could be negated by the simple expedient of wearing gloves. Today, would-be murderers have to negotiate a minefield of evidential hazards and risks to stand any chance of avoiding detection. They have to avoid being caught on CCTV as they travel to and from the murder scene (which means avoiding motorways, gas stations, shops, ATMs and other locations that are likely to have have cameras in operation). They have to remember to turn their mobile phone off, and make sure that the car they are driving doesn’t have an anti-theft tracking device installed. At the murder scene they have to be careful not to leave their DNA – including saliva, blood, hairs and so on – or fibres of any kind that could possibly be traced back to them. This is a lot more difficult than it sounds. A single eyelash is enough to put someone behind bars for the rest of his or her life. They also have to worry about tyre tracks, ballistic analysis and gunpowder residue (if they are using a firearm), blood stains, even satellite photos (which can be used to prove, for example, that their car wasn’t where they claim it was at the time of the murder) – and, of course, they still have to avoid leaving their fingerprints at the scene.

CCTV camera The most significant development in recent decades has been the proliferation of information and communication technology. Whereas previously the police apprehended criminals by following their physical trail, they are now just as likely to catch them by following their digital trail. It is virtually impossible now for a person to go anywhere, or carry out a transaction of any kind, without leaving a permanent electronic record of their movements. Every phone call and text message is logged. Every item purchased in a shop has a bar code which can be used to discover when and where the item was bought, and every receipt is time and date stamped. Every visit to a bar, a restaurant, a bank – or just about any place of business – is routinely recorded on CCTV. Surveillance cameras are everywhere, and increasingly they are being used in conjunction with facial and car license plate recognition systems. The days when a murder suspect could claim that they were in a different town at the time the murder was committed are over.

While it is not possible to prove a direct cause-and-effect relationship between increased surveillance and reduced crime levels – obviously there may also be other factors involved – it is noteworthy that the homicide rates in almost all developed countries of the world have been falling steadily since the 1990s, when CCTV began to be widely used, with the steepest drops occurring in large cities, where video surveillance is most prevalent. In 2012, for example, there were 414 homicides recorded in New York, the lowest number since records began. Serious crime rates in the UK have also been steadily declining as CCTV and other forms of electronic surveillance have increased.

It would take an exceptionally clever and calculating person to murder someone with whom they are known to have a connection, or from whose death they stand to profit in some way, without leaving any evidence connecting them to the crime. They would have to devise a meticulous plan which took all the factors mentioned above into account. However, it is axiomatic that the more elaborate the plan, the more scope there is for something to go wrong. Not even the most calculating person can foresee every eventuality. A flat tyre, a random police stop, or some other unexpected occurrence can throw a spanner into the works of even the best laid murder scheme. The annals of criminal history are littered with examples of “perfect crimes” that came undone when the unexpected intervened. For example, quite a few serial killers – including some who had outwitted the police for years – were caught after they got stopped by the police for minor traffic violations. Peter Sutcliffe, the infamous “Yorkshire Ripper” who was convicted of murdering 13 women in the UK, was caught when a routine police check revealed that the car he was driving was fitted with false number plates. American serial killer Ted Bundy, who murdered at least 30 and possibly as many as 100 young women, was finally arrested after he failed to pull over for a random traffic stop by a Utah Highway Patrol officer. When the officer searched Bundy’s car, he found a “rape and murder kit” consisting of an ice pick, a flashlight, a pair of gloves, torn strips of sheeting, a ski mask and a pair of handcuffs. And the New York serial killer Joel Rifkin, who was convicted of the murder of nine women (although he confessed to killing 17), was caught after police stopped him for a routine traffic offense and found the decomposing body of a woman wrapped in tarpaulin in the back of his vehicle.



Serial killers Peter Sutcliffe, Ted Bundy and Joel Rifkin were all apprehended after routine traffic checks.

Some murderers try to minimize the risk of getting caught by paying someone else to do their killing for them. This allows them to be somewhere else at the time of the murder, in full view of witnesses. However, involving a third party in a murder plot carries its own risks. What if the hired killer gets caught and points the finger of blame at the person who hired him (and hired killers are almost exclusively men)? What if he confides details of the plan to his wife or girlfriend and subsequently has an acrimonious break-up with her? Or what if he finds religion a few years down the road and decides to confess his crimes to purge his soul? Even the most hardened criminals have been known to develop a conscience and reveal the details of their past crimes to the police years or even decades later.

Hitman Hiring a professional killer might seem like a clever way to commit murder and get away with it, but what it actually does is make the person who did the hiring permanently dependent for their freedom on the silence of the person they hired. It also leaves them open to being blackmailed, particularly if there is a large inheritance or insurance payout involved. The fact that the hit man would face murder charges himself if he went to the police is not going to deter him from demanding payment in return for his continued silence. Not if he’s hard up for cash and the person who hired him has come into a fortune as a result of the murder. Criminals have a perverse sense of entitlement, and the chances are that as soon as he’s spent the money he was paid to carry out the “hit”, he’s going to reason that he deserves a bigger share of the spoils. After all, he’s the one who did all the work and took the biggest risks, right? If he’s in dire financial straits he has nothing to lose by demanding more cash. The person who hired him, on the other hand, has a great deal to lose.

I should perhaps point out here that the glamourised Hollywood image of a hit man as a highly-trained assassin who takes professional pride in his “work” has very little basis in reality. In the real world, contract killers are usually opportunistic, “general purpose” criminals who are willing to do anything for money. There is nothing remotely professional or glamourous about them.

Fingerprint More than one third of murder victims are killed by members of their own family, by spouses, or by close acquaintances. But very few of these murders are premeditated or carefully-planned. Most are the result of domestic arguments that escalated out of control. Planned murders are much rarer; but, again, there is really no way for anyone to determine to what extent this is because foul play was never suspected. While it is possible to put a figure on unsolved murders (in the US it is just under 40%), it will never be possible to estimate the number of murders that are never identified as such. They will always be “known unknowns”. However, it is reasonable to assume that intelligent killers would be smart enough to figure out that the best way to avoid detection is to make the murder look like an accident, or suicide, or death from natural causes. Because if it looks like a murder, it gets the full CSI treatment.

One would assume that with all these advances in forensic science, getting away with murder would be a lot harder today than it was in the past. And yet the percentage of homicides for which a suspect is charged and convicted has been dropping steadily over the last several decades. How is this possible? Well, for one thing the motives that drive people to commit murder – greed, revenge, jealousy and so on – are as powerful as they ever were, and, despite advances in detection technology, there is no shortage of killers willing to pit their wits against detectives and crime scene investigators. And, like most people, criminals watch CSI and other forensic programmes on television and visit crime-related websites, so they know what kind of evidence investigators look for, and what mistakes to avoid making. Increasingly, murderers are using bleach to wash out and destroy DNA, and they are far more careful to use gloves during the commission of the crime and the disposal of the body. Some killers have even been known to wear CSI-type anti contamination coveralls to avoid leaving fibres, hairs, skin cells, saliva and other microscopic evidence at the scene. The challenge facing forensic scientists and crime scene investigators is to stay one step ahead of the criminals who take note of their methods. But the main reason for the low detection rate, particularly in the United States, is the dramatic increase in gang-related homicides. According to FBI figures, as many as 75% of all murders carried out in the US are in some way gang-related. These killings are much less likely to be solved than other types of murder because witnesses are often reluctant to come forward for fear of reprisals, and because they tend to occur in clandestine environments. The victims are usually gang members, prostitutes, runaways, drug addicts, drifters and others who live on the fringes of society and put themselves in harm’s way. In some cases, innocent and uninvolved members of the public are killed in the crossfire, or in random drive-by shootings. It is the sheer randomness of these killings, and the lack of any clear motive, which makes them so difficult to solve. When gang-related murders are excluded from the figures, it turns out that that the conviction rate for “normal” murders is actually quite high, in the region of 90%.

CSI Kit It is easier, in many ways, for someone to get away with murdering a member of their own family than it is to get away with murdering a stranger. It is certainly easier for them to make the murder look like an accident, suicide, or death from natural causes, because not only do they have access to their intended victim, they also have intimate knowledge of their habits, their daily routine, their medical history and so on. For example, if the intended victim has a history of severe depression, no one will be too surprised if they are found dead with a gun in their hand and a bullet hole in their head. And if the victim is an elderly person who was known to have a weak heart or some other life-threatening condition, no red flags are likely to be raised if they are found dead in their bed one morning (there are many poisons that leave no signs and are virtually untraceable unless the pathologist or medical examiner knows exactly what he or she is looking for, even assuming that the death is flagged as suspicious). In many instances the decision on whether to sign a medical certificate or refer the death to the police and the coroner for further investigation is left to the doctor in attendance – this is often the deceased person’s family physician – who may have no expertise at all in spotting signs of foul play. Once a death certificate has been signed, the body can be cremated, and with it vital forensic clues. The downside of murdering a family member, from the killer’s point of view, is that if murder is suspected, the number of possible suspects is likely to be limited to just a few people.

Lab technician Fictional detectives usually have no trouble at all finding proof that a person was murdered, and did not commit suicide or die in an accident, but in reality it is often impossible to determine the manner of death, as distinct from the medical cause of death. It may be possible to ascertain that a person found dead at the bottom of a flight of stairs died from a broken neck or a fatal head injury, but finding evidence which can be used to determine whether they fell down the stairs or were pushed is a very different matter. Suicides and accidental deaths are always looked at closely, of course, but unless there are suspicious circumstances, they are unlikely to receive more than routine and cursory attention. It should be remembered that, while fatal accidents and suicides are events that most people rarely if ever encounter in their lives, they are common and everyday occurrences to the police, the emergency services, medical personnel and pathologists. In the United States, accidents in the home are one of the leading causes of death. Around 35,000 people die from accidental poisoning each year (perhaps surprisingly, this is roughly the same number of people as are killed in road traffic accidents). On average, 25,000 people die in falls every year, and around 36,000 people commit suicide. There are twice as many suicides as there are homicides. In fact suicide is America’s eighth leading cause of death. So there is no automatic suspicion attached to sudden deaths of this kind, unless, as I said, there are obvious indications of foul play. In general, the police are reluctant to intrude on grieving families, and will usually only do so if they have specific reasons for suspecting that the death may have been a homicide. The level of suspicion required to trigger a full homicide investigation differs from one jurisdiction to another, but in general investigators in cities in which a number of homicides are reported every day are less likely to go looking for evidence of murder than investigators in places where murders are rare, since they are often struggling to cope with their existing caseload. In many cases it comes down to allocation of resources, with priority given to cases which look as if they can be easily solved.

It is difficult to gauge, with any degree of accuracy, the extent to which advances in forensic science have made getting away with murder more difficult. Clearly, homicides are being solved today through examination of forensic evidence that would have been impossible to detect or analyze a few decades ago. Cold cases – and in particular rape-murders, because the evidence in these cases usually includes body fluids – are being solved through DNA matching, in some cases twenty or thirty years after the perpetrator thought he had escaped justice. But will the “DNA advantage” continue? Or will criminals become increasingly careful not to leave their DNA at the scene of their crime? It is important to remember that the rapists and murderers whose DNA is now being used to implicate them in past crimes are not being caught because they were stupid or careless. The type of evidence they left behind wasn’t evidence two or three decades ago. They could not have imagined that in the future it would be possible to identify a person from a microscopic trace of their DNA. That idea would probably have seemed like science fiction to them. Modern-day criminals, on the other hand, are fully aware of the power of DNA evidence. And while it is a lot harder for someone to avoid leaving their DNA at the scene of a violent crime than it is, say, to avoid leaving their fingerprints, it can be done. In fact DNA has a major weakness compared with fingerprint evidence: it can be transferred from one location to another, making the manipulation of DNA evidence not only possible, but quite easy. In other words, DNA can be deliberately “planted”. It can also be transferred accidentally, by investigators at the scene. And while analysis can determine the identity of a person from a DNA sample, it cannot say anything about how that sample came to be where it was found.



Lab technician

As I mentioned above, most murders are sloppy and either unplanned or badly planned, and there is rarely any mystery as to the identity of the person responsible. These cases are processed rather than solved, and it isn’t necessary to present DNA evidence in order to secure a conviction. In cases where the victim was murdered by someone in their close circle of relatives and friends, DNA is usually of no value anyway, since one would expect the DNA of a person’s relatives and friends to be found at locations at which they interacted with him or her on a daily basis.

It should be noted that there is usually a big difference between detection rates and successful prosecutions. In fact the term “crime detection rate” is a misnomer, since it has nothing to do with the number of crimes detected. Crimes that are not detected can’t be recorded, because by definition no one knows about them. But even leaving that quibble aside, detection rates usually bear little or no relationship to the number of crimes that have been solved. “Detection rate” means different things in different countries, and even in different states. In many cases the term is used to refer to the percentage of cases in which someone is arrested in connection with a crime, and the figures say nothing about whether they were subsequently charged and convicted. In some countries the detection rate includes suspects who are charged, but takes no account of whether they are successfully prosecuted. It is not uncommon for charges to be reduced, or even dropped altogether. Nor is it unusual, of course, for defendants to be found not guilty. In these jurisdictions, a police department can improve its detection rate – and thereby convey the impression that it is solving more cases – simply by making more arrests, even if they do not lead to convictions. In a recent case involving the Irish police, the Garda, it emerged that the term “detection rate” was being used by them to include cases where they “knew or had a rough idea of who committed a crime”, even when there was insufficient evidence to make an arrest, let alone secure a conviction. These cases were being recorded as “solved”.

Another way police departments improve their detection or “clear up” rate is by getting offenders to confess to other crimes in return for credit from the courts. This practice, which is very common, allows police to record the crimes as solved, improving the detection rates on which their performance is assessed. It is not unusual for suspects to ask for dozens or even hundreds of other crimes to be “taken into consideration”. A person charged with housebreaking, for example, might be persuaded to ask for 200 other cases to be taken into account. In return for this cooperation, he is rewarded with a lenient sentence. These 200 cases are then recorded as having been “cleared up”. Some lawyers have expressed concern that the system could lead to police putting pressure on suspects to confess to crimes they have not committed.

Lawyers doing deal Deals are also done, especially in the case of serious crimes like murder. Charges against one offender are dropped on the condition that they agree to give evidence against their co-defendant. The person released is often as culpable as the person convicted, but the stark choice facing the prosecutor may be to let two killers go free because there isn’t enough evidence against them to secure a conviction, or allow one to go free in order to secure a conviction against the other.

When police departments boast that their crime detection rate was higher this year than it was last year, this claim is quite meaningless unless one knows precisely how the figures were arrived at. In fact there are so many ways in which detection rate figures can be manipulated and “finessed”, a reasonable person might be inclined to regard them as nothing more than a police public relations opportunity, and take them with a generous grain of salt. Where homicides are concerned, the only figure that matters is the number of successful convictions.

One final point (or should I say “just one more thing”?). The quality of a defendant’s legal representation can make all the difference in the world as to whether or not they get convicted. A good lawyer – which invariably means an expensive lawyer – can often persuade a jury to return a not guilty verdict even when the evidence pointing to the defendant’s guilt appears to be overwhelming. Most murder suspects make self-incriminating statements to the police before they get to see a lawyer, and they are more likely to be convicted on their own evidence than on the evidence found at the scene. So while in theory the same laws may apply equally to the rich and the poor, the conviction rate – especially for murder – is certainly a lot lower among those who can afford top class legal counsel. In fact the wealthier a person is, the less likely they are to be arrested, face criminal charges, be found guilty, be given a custodial sentence, or be denied parole. This sifting process means that a wealthy person is three to four times more likely to get away with murder than a poor one.


Zak Martin





Copyright © 2017 Zak Martin. All Rights Reserved.