Advances in forensic technology mean even the smallest shred of evidence can be used to crack major crimes. Telegraph & Argus Crime Reporter Joanne Earp spent a shift with the Scenes of Crime Office (SOCO) to find out more.

IT IS 8.30am and Bradford SOCO team member Nick Bell is on his way to Buttershaw.

A property has been targeted by vandals overnight and the culprit has left muddy footprints all over the door.

With nothing stolen and no witnesses it will be difficult for police to make a successful detection.

Even so, the principles of SOCO remain the same - get whatever you can now. You might not get a second chance.

Nick dusts the door with silver powder and uses a sheet of sticky tape to take an impression of one of the prints.

It will be logged on the case file and sent off to the force's footwear specialist in Wakefield, where each print is added to a database.

Nick explained: "Fingerprints are the best evidence we have because they are unique and cheap to process.

"DNA profiles are as technologically advanced as you can get, but footprints can also be vital.

"The markings on the sole of a shoe change every time it is worn. If we take a sample of a footwear mark it can be matched to a specific shoe."

Markings can also be photographed or cast in plaster, and in summer SOCO use static electricity to lift dusty prints and tyre marks. A machine literally sucks up the particles, creating an identical pattern.

With technology advancing at a rate of knots, you would be forgiven for thinking the SOCO team is made up of scientists and chemical experts.

But Nick is a civilian member of West Yorkshire Police. He worked at Morley for six months before joining Bradford's SOCO team in 1993.

Prior to that he worked in a bank, for Marks & Spencer and at a job centre. "You get quite a mix of people in this job," he said.

"We've got a former Group 4 security officer, ex-builder, ex-undertaker and a former nurse. You don't have to come from a scientific background, although it's preferred nowadays."

Team supervisor Rupert Nicholson adds: "It's not all science. There's also a big public- relations role which comes with the job.

"Many of the people we visit are understandably very upset about what's happened. In some cases they are very agitated when we arrive. We have to use our communication skills to calm them down."

For many people the attraction of the job is that you never know what is around the corner.

Nick said: "You can go from spending five minutes at a house burglary to days at a Murder scene."

Scenes of Crimes Officers also attend serious road traffic accidents and fires - to take photographs of the scene and collect forensic evidence.

And they are required to take photographs at post mortem examinations and sudden deaths to help with identification or any ensuing investigation.

Next we pay a visit to a vehicle recovery firm in Manchester Road, Bradford, where the SOCO team has been called out to test two stolen vehicles.

After searching through his 'box of tricks,' Nick returns with a pair of tweezers to recover three cigarette ends from a car ashtray.

"You can get a DNA sample from the saliva on the end of a cigarette," he points out.

"They may belong to the owner, but it is always best to seize them just in case. You don't get a second chance in this job.

"I haven't found any fingerprints, but if we do, we leave an elimination kit inside the vehicle. They could be anyone's so we get the owner to take his or her fingerprints and send them back for elimination purposes."

The forensic evidence taken by SOCO can be split into three areas - prints, fluids and fibres.

Anything from a spot of blood or fragment of glass to a flake of paint or cigarette butt can prove vital to an investigation.

Swabs of blood are often used in murder inquiries to produce a genetic profile of the killer -- placing him or her at the scene of the crime.

Nick said: "You can't avoid leaving fibres or hairs at a scene and if you cut yourself on glass or a weapon you can't stop yourself from bleeding.

"DNA profiles can be logged on the national database. Then one day detectives can send off a routine test and end up getting a match for a crime committed years ago in another part of the country."

DNA clue that nailed sex brute

Bradford rapist Christopher Hodgson was this week beginning a life behind bars after he was caught by a routine DNA test.

The 37-year-old, pictured, from Holme Wood, Bradford, was arrested in Halifax last year for alleged motoring offences.

A sample of his DNA was sent to the national database - where it brought up a match against an unsolved attack on a 13-year-old girl in Pudsey.

At Leeds Crown Court last week, Hodgson admitting dragging the girl off the street in October 1997 and raping her three times.

Detective Inspector Trevor Ambler, of Pudsey CID, said: "At the time of the attack we carried out hundreds of swab tests on Pudsey men, but Hodgson was never tested because he was living in Halifax.

"When he was arrested last year he was given a routine test and it turned out to be a match.

"Forensic science techniques move on very quickly. No case is ever closed. They are left on file and constantly reviewed.

"One match on a DNA test can crack a case, or series of cases, just like that.

"That's what happened with Christopher Hodgson. It just goes to show the benefits of DNA."

22 years on, but the trail is far from cold

Advances in DNA technology enabled detectives to re-open a 22-year investigation into the murder of a Shipley housewife.

Mary Gregson was sexually assaulted and strangled in August 1977 as she walked along the Leeds-Liverpool Canal towpath.

Murder squad detectives compiled a list of 9,000 possible suspects but were unable to get any kind of DNA match from the techniques available at the time.

The new technique, called SGM Plus, is the most advanced in the world and is so sensitive it can provide genetic samples from a minute speck of dandruff or even a handshake.

It can analyse dried-up evidence such as blood or semen -- which allowed detectives to re-open the case in September last year.

They now have a genetic profile of Mary's killer and have been able to eliminate 750,000 convicted criminals contained on the national DNA database, including Yorkshire Ripper Peter Sutcliffe.

They have also begun eliminating people from the original list of suspects by means of simple swab tests and are confident they will one day come across a match. The Forensic Science Service claims SGM Plus is so powerful that the chance of someone else sharing the same DNA as the suspect is smaller than one in a billion.

Senior investigating officer Detective Chief Superintendent Brian Taylor said: "We now have a genetic profile of Mary's killer, which means we are in a position to either eliminate or implicate by way of a simple swab test.

"The new DNA technique has enabled us to eliminate more than 400 people from the original list of suspects drawn up in the 1970s."

The national criminal intelligence DNA database was set up in 1995. The chances of a stain found at a crime scene being matched to a name on the list was 40 per cent.

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