How do forensic scientists track down evidence? Ever since Sherlock Holmes and his magnifying glass, we have been fascinated by detectives looking for clues. ANGELA SINGER begins a series on the work of forensic scientists at the Forensic Science Service
How do forensic scientists track down evidence? Ever since Sherlock Holmes and his magnifying glass, we have been fascinated by detectives looking for clues. ANGELA SINGER begins a series on the work of forensic scientists at the Forensic Science Service in Huntingdon. Next week: DNA, documents and drugs. Pictures: HELEN DRAKE
SUE LAVER put on a pair of large pink knickers and asked a colleague to rip them off her.
It was important the knickers were torn, in order to see where they would tear in a sexual attack.
"We have to be absolutely objective. We don't work for the prosecution. We don't work for the defence. We are here to see that the evidence matches the story.
"Sometimes you can get a torn garment but when you put it under a microscope you can see that it has been cut with scissors. There has been assistance to the damage."
Sue, a biological reporting officer, works for the Forensic Science Service, acknowledged as the best in the world for what it does. It has six laboratories in the UK, including Sue's at Hinchingbrooke in Huntingdon.
The sexual offences section of the lab is not for the squeamish. It is all about finding the right body fluids in the right places that will or won't support evidence.
In one example, a 13-year-old girl accused a man of kissing her nipples. He denied any involvement with the girl until his DNA was found in her bra. He then changed his story to say that he and the girl had wiped their hands on the same towel.
"It was not feasible that the DNA would have gone from his hands to a shared towel and ended up inside her bra. In the end he admitted the offence. It is interesting how people will change their story in an attempt to make it fit the evidence."
Because DNA evidence is so crucial, findings are double and triple checked at every point that information is discovered and recorded. Part of Sue's job is to go to court and read out a report on where DNA has been found and its significance.
"When one of the team finds stains of blood or semen or saliva, I will go and look at it myself. I could not possibly stand in court and say that I have see something that I have not. I have to have seen it."
Another part of her job is to train police officers on procedures immediately after someone has reported a rape. "I explain that we will need a full range of swabs, not just from the vagina but from the whole region of the anus as well, and finger nail samples.
"If the victim has fought back, the attacker's DNA could be under her nails.
"A lot of rapists kiss their victims, if the victim has been kissed, bitten or held down, that could be a good source of DNA."
A leaflet Sue leaves with police officers explains that samples should be taken as soon as possible and that until the samples have been taken, the complainant should not eat, drink, clean their teeth, wash, bathe or defecate. Police should also take samples from the victim's partner for elimination purposes. Any bedding, clothes, tissues or towels involved should also be kept for DNA examination.
The FSS works for a range of organisations, not just the police.
"We were asked to examine a contaminated item, some linen, for Rentokil. They suspected it was blood. Actually, it wasn't blood, it was glue."
But Sue's day is not always spent looking at stains or tearing underwear, or giving guidance to police officers. "I can spend my whole day in the evidence room signing labels or I could be sitting all day looking at slides of semen or I could be advising people."
Like everyone I met at the Forensic Science Lab, Sue, who has a degree in molecular and cellular biology from Huddersfield, is entirely engaged with her work. I wondered what conversations would be like at the lab Christmas party.
"People overhearing our conversations would find them bizarre," she said. "We would be talking about body fluids and orifices quite naturally. You forget what it's like to be normal.