Forensics: What Bugs, Burns, Prints, DNA and More Tell Us About Crime

by Val McDermid

Locard Exchange Principle: ‘Every contact leaves a trace.’

In the UK, it’s possible to get a DNA profile in just nine hours on a straightforward bloodstain, and the cost goes down depending on the turnaround time required.

Wow. Which is why everyone should be put on a database when born. The only people who should be afraid then are those who are criminals.

A fingertip search revealed three bullet casings from a 9 mm handgun – one of the standard firearms used by career criminals, easily obtained even in the UK where guns are illegal.

‘I found that quite annoying personally, but I actually see the need for an adversarial system. I was challenged but ultimately that strengthened the case because it was clear that there were no issues with the evidence. Ten years down the line we’re not going to have an appeal in that case saying the evidence could have been tampered with. I’d rather get it out in the open now. Let’s challenge it now, let’s face the scrutiny.’

When the fire abates four days later, it has destroyed most of the medieval City of London, including more than 13,000 houses, 87 churches and St Paul’s Cathedral. Roughly 70,000 of the city’s population of 80,000 are suddenly homeless.

He incubates the live maggots until they become flies as confirmation of his identification. He examines the anatomy of the preserved maggots carefully to assess their stage of growth. Combining his assessment with the temperature data, he plots a graph leading back in time to the point when the mother blowfly laid her eggs. This is usually a key piece of information, and an entomologist’s most valuable offering to the forensic puzzle.

The element radium is structurally related to calcium, he explained. When it is ingested, the body treats it like calcium: some is metabolised, some is transmitted to the nerves and muscles, most is deposited in the bones.

Our fingerprints are part of us from before birth; they first appear in the tenth week of pregnancy, when the foetus measures only 8 cm. As one of the three layers of tissue that make up the foetus’s skin – the basal layer – starts to grow at faster rate than the other two, ridges form to relieve the resulting stresses, ‘like the buckling of land masses under compression’.

ghetto blaster,

In Stafford-Smith’s words, ‘Capital punishment means those without the capital get the punishment.’

In the adversarial system, a fair trial is impossible without access to the same resources, what under UK law is known as ‘equality of arms.’ At the very least Kris Maharaj should have had a good lawyer and a ballistics expert. If any theory is to be trusted – whether it is a theory of guilt or anything else – it needs to be scrutinised and criticised by competent outsiders. The scientific method demands it.

They make sacrifices so that the rest of us can live knowing that, if we are the victims of crime, the perpetrators will be brought to justice. They do not guard their knowledge jealously; they share it as widely as possible in the hope that one of their colleagues may use it as a springboard for the next leap forward.