The Perfect Murder

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

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.

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

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.

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.

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.

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. The ones that are planned usually have financial gain as the motive.

It is, in many ways, easier for someone to get away with murdering a member of their own family than it is to murder a stranger. Not only do they have access to their intended victim, but they also possess intimate knowledge of their habits, daily routines, and medical histories—crucial information that makes it far easier to stage a death as an accident, suicide, or natural cause. For instance, if the victim has a known history of severe depression, few will question a death that presents as a self-inflicted gunshot wound. Similarly, if the deceased is elderly and had a weak heart or some other serious condition, little suspicion will arise if they are found lifeless in bed—especially considering that many poisons leave no trace unless the examiner knows precisely what to test for, and that is only if the death is even flagged as suspicious. Often, the decision to refer a death for investigation lies with the attending doctor—frequently the family physician—who may have no training in identifying subtle signs of foul play. Once the death certificate is signed, the body can be cremated, and with it any potential forensic evidence.

However, for all this apparent ease, it would still take an exceptionally clever and calculating person to murder someone close to them—especially someone from whose death they stand to profit—without leaving behind any incriminating trace. They would need to construct a meticulous plan that accounted for every detail: access, motive, opportunity, and the manipulation of post-mortem appearances. Yet the more elaborate the plan, the more vulnerable it becomes to disruption. 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. If suspicion does arise, the killer’s intimate connection to the victim makes them one of the first to fall under scrutiny.

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.

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.