Detectives investigating the cold-case murder of a mother-of-three who was battered to death in her own home in 1995 believe new DNA evidence could help solve the mystery. Janet Brown was found naked, gagged with packing tape with her arms cuffed behind her back at the foot of the stairs of her family home in Radnage, near Chinnor in Buckinghamshire. Mrs Brown's two daughters Roxanne, 38, and Zara, 43, described their hother as a 'kind and loving nurse' claiming the horror of the crime 'stays with us every day. Janet Brown, pictured, was murdered at her family home 20 years ago by an unknown assailant . Builders found Mrs Brown's naked body dumped at the bottom of the stairs of her home, pictured . The killer handcuffed Mrs Brown's hands behind her back hand gagged her with packing tape . Mrs Brown's body was found on April 10, 1995. According to the Brown sisters: 'She was attacked and killed in our family home - a place where we should all be safe.' They said they believed that their mother's murder had been pre-planned. On the night she was killed, Mrs Brown was home alone. Her two daughters and her son Benedict, then 21, had gone out. The following day, the 51-year-old nurse's naked body was found at the foot of the stairs by builders who had turned up to do work on the detached house in Sprigs Holly Lane, Radnage near Chinnor in Buckinghamshire. A post mortem revealed she died of head injuries, which detectives believe were probably inflicted by a blunt instrument like a crowbar. The motive remains unclear with police describing the circumstances of the crime as 'unusual', adding they 'keeping an open mind'. One possible line of inquiry was that it had been a break-in gone wrong, but while a window was broken and the burglar alarm triggered, nothing was taken from the home. There was also no evidence Mrs Brown had been sexually assaulted. Peter Beirne, right, of the cold case squad and Mrs Brown's daughters Roxanne, centre and Zara, right, appealed for information about the 'heinous' crime revealing forensics experts now had the suspect's DNA . There was no evidence of a sexual assault at the crime scene in Radnage in Buckinghamshire, pictured . Members of Mrs Brown's family, pictured, made a similar appeal 20 years ago following her brutal murder . Detectives said that whomever the attacker was had brought the hand-cuffs and tape used to restrain Mrs Brown along with them. Despite what police called a 'thorough and professional investigation' at the time the killer has eluded capture, leaving her broken-hearted family without justice. In a bid to finally find the culprit, detectives turned to modern scientific techniques to analyse clues found at the time. Peter Beirne, the head of Thames Valley Police's major crime investigation review team, revealed a DNA sample belonging to an unknown person had now been successfully extracted. 'These new tests have produced a DNA sample,' he said. 'It does not belong to the family and we believe it could be a vital piece of evidence linking the killer to the scene.' He would not reveal what item the DNA sample was taken from. Police say there are plans to swab a number of people who featured in the original investigation, but stress there were 'no suspects, as such' - there have never been any arrests over the case. Instead, Mr Beirne said he was first appealing to the public to put forward names of anyone they believe may have been involved, who would then be tested. It would then be 'a simple task to either eliminate or implicate people as the source of the DNA', he added. Mr Beirne, a retired veteran police officer with more than 30 years experience as a detective, said if nothing useful comes to light then investigators may then look at 'a potential mass screening' in the area. He said: 'Janet's death left three children without a mother. 'We want to bring justice to Janet's family. 'If people have suspicions, I would urge them to contact police.' Mr Beirne added: 'Somebody out there knows who killed Janet - we're asking them to make contact.' Also appealing to the public, Roxanne Brown said: 'We need your help to find them.' It was revealed had she survived, Mrs Brown would now be a grandmother with detectives saying the youngsters had been robbed of the chance to know her. A £20,000 reward is being offered for information leading to a successful conviction of the killer. Anyone who believes they may have any information about the crime is urged to call the police on 101 or contact Crimestoppers anonymously on 0800 555 111. Cold case detectives have relaunched a murder inquiry 25 years after a man was reported missing by his girlfriend. Andrew Bedford was 27-years-old when he disappeared in 1990. He was last seen eating a takeaway, possibly fish and chips, in a car in Ramsey, Cambridgeshire. The Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit has today issued a fresh appeal for information on what would have been his 52nd birthday. Andrew Bedford was 27 when he went missing from a takeaway in Ramsay, Cambridgeshire in 1990 . Officers say that given the circumstances surrounding his disappearance and the amount of time that has passed, they are now confident he was murdered. They believe he was killed on September 28 with a shotgun at a garage called Mongrel Cars, which no longer exists, in the market town. Detective Inspector Ian Simmons said: 'A team of detectives from the three force Major Investigations Unit is devoted to the cold case and we want to speak to anyone who has any information about Mr Bedford's disappearance and death. 'We would particularly like to speak to people who came forward before but maybe did not tell us everything they knew. 'No unsolved crime is ever closed. Where there is an opportunity to bring those who have escaped justice to account we will. 'We are in contact with Mr Bedford's family and keeping them fully informed of developments.' Mr Bedford, then of Tweet Street, Huntingdon, was last seen in a light blue Ford Cortina at 6.20pm on September 28 1990 in Factory Bank, Ramsey. He was reported missing the next day. He was wearing overalls, a khaki jumper, jeans and trainers and was described as 5ft 8ins, of medium build, with mousey blond, curly, shoulder-length hair and various tattoos. Despite a huge police inquiry, which included extensive searches by helicopter and specialist divers, a nationwide poster campaign and a reconstruction on Crimestoppers, no trace of Mr Bedford was found. Three people were arrested but released without charge. The prime suspect for the shooting is now dead but others who were involved have never been brought to justice, the force said. Anyone with information should contact the Major Crime Unit on 101 or Crimestoppers, anonymously, on 0800 555111.
Janet Brown was killed at her Buckinghamshire home in April 1995 .
She was beaten with an iron bar and left naked at the foot of her stairs .
Detectives at the time said there was no sign of any sexual assault .
Now cold-case squad detectives said they have crucial new evidence .