There are 10 unsolved murders in the Northumbria Police area, going back more than 20 years. Daniel Cochlin looks at how new groundbreaking DNA kits could solve some of the area's most notorious killings.
The ground was thick with snow in the early hours of Christmas Eve 1993 when takeaway driver Paul Logan left the Golden Flower Chinese restaurant in Shotley Bridge to deliver an order.
The 25-year-old had been called to Blue House Farm, Shotley Bridge, on Northumberland's border with County Durham, by a call from a telephone kiosk at the junction of Snows Green Road and Benfieldside Road in the village.
When the father-of-two arrived at the farmhouse just before 10pm, he was told by the householders that no meal had been ordered. He left, but the householders later noticed his cream Peugeot car was still at the end of the lane leading up to their home.
Mr Logan, from Blackhill, Consett, was found 50 yards away from the empty car, which was left with the lights on and doors open. He had severe head injuries inflicted by a blunt instrument which was never recovered.
The murder has remained a mystery to detectives, who have regularly reviewed the case in the intervening years - taking 1,200 statements, looking at over 2,000 lines of inquiry and producing 4,000 documents.
They have vowed not to abandon the inquiry despite the length of time which has passed, but admitted earlier this year, after another appeal, that they had received a "disappointing" response from the public.
However, a glimmer of hope has been ignited over the killing - and the nine others still unsolved in the Northumbria Police area - by a revolutionary DNA breakthrough.
Officers are trying out DNAboost, a new computer programme which can analyse tiny fragments of DNA, or samples of poor quality.
Detectives say tens of thousands of crimes could be cracked with the kits, and that, if the equipment proves successful, they will use it to look at the unsolved murders.
At the moment, it is being trialled on what police call "volume" crimes - such as burglary, assault and theft.
But Northumbria's Chief Insp Glynn Williams, of the scientific support unit, admits they hope to be able to use DNAboost to solve a number of cold cases - such as murders or rapes - and other high-profile crimes.
He said: "It is still the situation that we are piloting the programme, and it is too early to say how much success we could have with cold cases such as these.
"It is being used in volume crimes at the moment but, if DNAboost lives up to expectations, there is every possibility we will look at more serious categories of crime.
"It is a pilot and it is going to run as such for a little longer than we first thought but, rest assured, we do want to use it as much as possible if it works.
"It is potentially something that could be a huge help to the police because it gives you techniques that we simply do not have at the moment."
Northumbria is one of four forces in the UK piloting the technique, which claims to allow scientists to identify 40% more samples than at present.
The Forensic Science Service, which has brought out the pilot scheme, says the service can already handle more than 10,000 DNA crime stain samples each month, and about 50,000 DNA samples from individuals.
At the time of the last appeal about Mr Logan's murder, Det Insp Chris Sharman, from the force's homicide squad, said: "A lot has happened over the past 12 years and people have grown up, married and moved.
"However, one group of people who can't move on is Paul's family who are still searching for answers as to what happened that night.
"This inquiry may be 12 years old but we are absolutely determined to catch whoever carried out this vicious attack and bring them to justice."
John Welch Father-of-two John Welch was killed at the Swallow Hotel - now called the Chasley - in Newgate Street, Newcastle.
Forty-five year old Mr Welch, from Lincoln, worked for a subsidiary of Ladbrokes and was on Tyneside to wind up the Macau Casino. He was due to meet colleagues for dinner and, when he didn't show up, they phoned the hotel.
Detectives believe that Welch went to answer a knock at the door and was confronted by the killer who hit him over the head.
A post-mortem examination revealed he suffered serious head injuries.
Prostitute Julie Perigo, 51, was murdered in her one-bedroom council flat in Kidderminster Road, Downhill, Sunderland, on May 23, 1986.
The mother-of-two died of shock and bleeding due to multiple stab wounds.
On the day that she died, Julie had told a friend she was meeting a client at lunchtime. This man has never been found.
Simon Martin, 14, of Amy Street, Southwick, Sunderland, was found battered to death in 1990 at the now-demolished Gillside House on Roker seafront, Sunderland.
Sixteen-year-old Alvin White was arrested and charged with the murder after one of his fingerprints was found at the scene, but the charge was discontinued five months later.
In 2000, Mr White, then 26 years of age, sued Northumbria Police, claiming wrongful arrest and malicious prosecution.
He lost his claim for damages but the judge did say detectives may be described as having been "heavy handed, insensitive and even incompetent" in their investigation of him.
Takeaway delivery driver Paul Logan was found battered to death in December 1993.
The 25-year-old father-of-two from Blackhill, Consett, County Durham, was lured to his death after answering a call at the Golden Flower Chinese restaurant in Shotley Bridge where he worked.
He was asked to deliver a meal to remote Blue House farm on the Northumberland and County Durham border. His killers lay in wait and his body was left in deep snow next to his Peugeot 205 car.
In a case that has baffled police, 10 men were arrested in 1997 but were later released on bail.
Tyneside hardman Viv Graham was killed on New Year's Eve 1993 just after he left The Queen's Head pub in Wallsend.
The killers had first smashed a window in the 34-year-old's Ford Cosworth car, then shot him three times at point-blank range.
The former pub and club doorman is believed to have been the victim of a gangland killing.
Sixty-one-year- old Hugh Ord was found battered at the back of his flat in Springhill Walk, Morpeth, in April 1995.
Detectives believe that he was likely to have known his killer and stepped outside to talk to him when he was attacked.
Three men and a woman were arrested and questioned in connection with the killing but were later released.
On February 17, 1996, Kevin Nightingale, 33, was shot outside his front door as he returned from work.
He was found by his wife and their 11-year-old daughter, Michelle, outside the family home in Drake Close, South Shields.
Mr Nightingale had worked for three years as a doorman at the now-closed Oz nightclub in the town when he was shot.
A family man, he took a hard stance against drugs and constantly warned his children of their dangers. But it was his desire to keep drugs, dealers and users out of the places he worked that may have led to his death.
Three people charged with killing Mr Nightingale walked free from court after the case against them was dropped for a second time in 2001.
Stephen Sweeney was found slumped over his desk at the Cascade furniture factory he ran in Stoneygate Industrial Estate, Felling, by his partner Carol Taylor and their seven-year-old daughter Siobhan on July 8, 1998.
He had been shot several times at point-blank range.
Mr Sweeney, 45, lived at Riverside, Hebburn.
A team of 60 detectives worked on the case after the shooting.
Their investigations into Mr Sweeney's background and associates revealed a picture of shady dealings and a firm in financial trouble.
Peter Beaumont Gowling
The body of convicted drug-money courier Peter Beaumont Gowling was found at his luxury flat on Osborne Road, Jesmond, Newcastle, by his girlfriend just before midnight on St Valentine's Day 2001.
The 52-year-old had been shot several times in the head, chest and back, with a small-calibre handgun.
Beaumont Gowling, also known as David Simpson, had been released from jail only three weeks beforehand.
He was jailed in 1997 for his involvement in a massive drug-money laundering operation.
Nineteen-year-old Scott Pritchard was found outside his home in Lindsay Close, Hendon, Sunderland, at about 7pm on Wednesday January 7, 2004. He was unconscious, with head injuries.
Scott was pronounced dead on arrival at Sunderland Royal Infirmary where a post-mortem examination later found his injuries had been caused by a blunt instrument.
He was single and had lived with his mother and younger brother and sister. Police said he had a wide circle of friends.
His father, Robert Stacey, then of Deerness Road, Hendon, was charged with murder but the charges were dropped in October 2005 by the Crown Prosecution Service.
Breakthrough may double cold case success
DNAboost allows scientists to bring clarity to a type of sample that was previously impossible to analyse.
Where more than one individual has touched a surface - a chair arm, for example - previous technology had a low success rate in distinguishing one person from another, particularly where only small amounts of DNA were left behind, or the material found was of poor quality.
DNAboost could boost crime detection rates by more than 15%. Makers claim it will be the biggest development in DNA analysis and interpretation since the Forensic Science Service conceived and introduced Low Copy Number, which enabled a match to be found from a minute sample of cells.
Scientists estimate that using the two techniques together could solve double the number of cold cases which have lain dormant for years.
The pilot has been running for three months, in Northumbria, West Yorkshire, South Yorkshire and Humberside police forces.
If it proves successful, it will be available to the rest of the UK's forces.