The evolution of forensic science is turning hopelessly unsolvable cold cases into convictions.
by Liz Porter
British armed robber Andrew Pearson probably never imagined he’d end up as the star of an anti-dandruff advertisement. He also probably never dreamed he’d get caught for the 1993 holdup in which he and two accomplices stole £38,000 from a caravan company in the Yorkshire city of Hull. After all, the masked and armed trio left an impressively clean crime scene behind them.
All that the police found afterwards was a stolen Vauxhall Cavalier, abandoned near the scene. Inside it were a few fingerprints, none of which produced a match to any prints already on file, and one small segment of black stocking – discarded, investigators assumed, after one of the robbers had used it as a mask. How could Pearson ever have thought that, 11 years on, DNA analysis of specks of dandruff on this mask would lead police straight to his door and earn him a 15-year prison sentence?
The storyline was so irresistible that the advertising copywriters for Head & Shoulders anti-dandruff shampoo didn’t even need to sex it up. The half-page advertisement that appeared in papers across the UK simply reproduced a tear-out of an article about the 2004 court case, adding the slogan “Don’t get caught with dandruff.”
The robbery was brutal but effective. On a pay day in July 1993, the 29-year-old roofer was one of a gang of three masked men, two armed with guns and one with a baseball bat, who stormed into the Hull headquarters of Atlas Caravans. The trio expected to make off with the £250,000 due to be paid to the company’s staff. They missed the main wages delivery, but still got away with £38,000.
During the robbery, office workers were told to lie on the floor, or someone’s head would be blown off, while one man was left with head injuries caused by flying glass – the consequence of one of the robbers firing his gun through a window.
Eleven years later, the victims found themselves reliving the trauma of that experience when they gave evidence at Pearson’s trial. But they were all reportedly thrilled by the advertisement, declaring it the perfect light relief after the stress of the witness box.
By the time Pearson faced court, his accomplices had still not been found, and there was no way that he was ever going to rat on them. Detective Mike Reed, who was in charge of the re-opened investigation, believed that Pearson was the man holding the baseball bat, rather than one of the guns. But even that conclusion came from witnesses’ descriptions, not from the criminal’s own admission.
Pearson had previously been a temporary employee of the company and was a habitual offender, with 76 convictions dating back to the 1970s for offences including burglary, robbery and assault. Despite the many times he had been arrested, however, it seems that he had had few fears – until his arrest in 2003 – of being caught for the armed robbery. In fact, he had been so confident that he had been living in a mobile caravan on an estate five minutes’ drive from the caravan company’s headquarters.
He could have been forgiven for assuming that the 1993 robbery had been forgotten.
In 2001, there had been blanket media coverage of another armed robbery at the same site. On that occasion, another equally violent but less competent threesome had been caught within a day of its overnight raid on the company’s office, during which a security guard had been killed. Newspaper reports on that break-in did not mention the unsolved 1993 incident.
But Pearson hadn’t counted on the diligence of the crime scene police investigating the first robbery. They had collected the section of stocking, which contained only the toe and part of the leg, in the hope of finding blood, saliva or hair roots suitable for the DNA profiling that was available at the time. They found none. But, running a roller covered in special forensic sticky tape over the stocking, they recovered 25 skin flakes which, when examined under a microscope, were confirmed as dandruff. These samples were too small for 1993’s DNA technology, so the tape containing the flakes was placed on a clean sheet of plastic acetate and stored.
The 1998 invention of “low copy number DNA,” a technique enabling a genetic profile to be obtained from samples as small as 15 or 20 cells, was first used on long-unsolved murders. By 2003, police were keen to see if the new technology could help them find the perpetrators of other unsolved cases. The carefully preserved dandruff flakes from the 1993 armed robbery arrived at scientist Dr. Jonathan Whitaker’s Birmingham laboratory in July 2003. The DNA profile that the scientist extracted from them was run against the 2-million profiles on the UK national database. As a man with a string of convictions, Pearson’s profile had been on the database for some years. The profile from the dandruff matched it.
After arresting Pearson, police took a buccal swab of skin cells from the inside of his cheek. Whitaker extracted Pearson’s DNA profile from the sample; it was an exact match for the profile from the dandruff flakes.
In November 2004, Whitaker was in a witness box in the Hull Crown Court, explaining to the jury that the match he had found between Andrew Pearson’s DNA profile and the one extracted from the dandruff meant one of two things: either the skin flakes came from Pearson, or they came from a person with exactly the same profile as Pearson. The chance of obtaining that profile from a person chosen at random in the UK was about 1 in 1 billion.
Pearson worked hard to explain to the jury why his DNA might have ended up on the stocking. He admitted that he might have been in the robbers’ car. He could have been given a lift, leaving his DNA on the back seat. He might have used the piece of stocking as a rag to mop his head. Or he could even have touched the stocking without being in the car.
Unimpressed with any of these alternatives, the jury spent only 75 minutes deliberating before finding him guilty of the robbery. Sentencing Pearson to 12 years for the robbery and three years for the possession of a firearm, the judge, Michael Murphy QC, warned other criminals that they should learn a lesson from this case. “As detection methods become more effective and sophisticated, even criminal behavior for which they feel they have evaded responsibility is likely to catch up with them. Justice will be done in the end.”
Pearson’s conviction did not close the case, but it is unlikely that either of his co-offenders will be prosecuted for this crime. As Pearson was facing court, detective Mike Reed was still on the track of one of his gun-wielding accomplices. Advances in fingerprint technology had enabled police to find a match for one of the sets of prints found on the stolen Vauxhall: a notorious and formerly Liverpool-based armed robber. By the time Reed went looking for him, the man had been released from prison after serving time for another armed robbery, and had vanished. The UK’s National Criminal Intelligence Service, which targets organized crime, was also looking for the suspect, who had moved on from armed robbery to a career as a cocaine dealer.
Reed finally interviewed the man in prison after he had been convicted of serious drug importation charges and given an 11-year sentence. He admitted that his “business” in 1993 had been car stealing, which made it plausible that his prints might be on one of the many cars he stole from the Liverpool area and then sold on. But he denied having taken part in the armed robbery.
Reed was more inclined to believe that the inmate was the robber who had fired his gun during the incident, but he couldn’t prove it. Meanwhile, without a trace of forensic evidence to help police find him, it seems that the third robber will never be even identified, let alone convicted.
