Terrified victims have described how the “well-spoken” raider seems to know the layout of their homes, down to where safes are hidden.He also shows a knowledge of their daily routines, often striking late at night, entering unlocked doors or windows, sometimes waiting until owners let their dogs out.During the raid on the Goodwood estate in January 2016, the Duke, 61, was struck on the head with a blunt object, before being forced to open a safe. High value watches stolen during burglaries by The Night WatcherCredit:Surrey Police/PA The Night Watcher raided Goodwood House, the home of the Duke and Duchess of RichmondCredit:David M. Benett /Getty Some of the family heirlooms stolen during the burglariesCredit:Sussex Police/Solent News & Photo Agency DNA evidence was found at the scene of one of the raids, but this has not been traced to any other offences.There is a database of British military personnel DNA, but this is used to identify bodies in the event of death.However, if police come forward with the name of an individual under suspicion of a crime, the DNA database can be made available to the police in their investigation. Items stolen in raids believed to have been carried out by the Night WatcherCredit:Surrey Police/PA The raider, who wears a balaclava and dark clothing, usually escapes on foot without leaving any forensic clues.He has struck seven times over the past three years in Surrey, Berkshire, Sussex and Kent, making off with more than £7 million in valuables. Similar raids have taken place around every six months, with detectives working on the theory that he strikes after spending the proceeds from each burglary.Det Insp Dee Fielding, from Surrey Police, said: “We do not believe this to be an opportunist burglar, but someone who has specialist knowledge and skills – possibly ex-forces or from a similar background.“The burglaries all appear to be the work of someone who knows exactly what they are doing and who is incredibly decisive in their actions. On each occasion, unnecessary levels of violence have been used.” Some of the family heirlooms stolen during the burglariesCredit:Sussex Police/Solent News & Photo Agency Police are hunting a violent armed burglar who uses “special forces” techniques and military-style expertise to stake out and strike at multi-million pound properties across the Home Counties.Among those targeted were the Duke and Duchess of Richmond, who were forced to hand over £700,000 of heirlooms after being tied up during a raid at Goodwood estate in Sussex.Police believe the burglar, dubbed The Night Watcher, spends months staking out secluded houses, sometimes hiding in the grounds, in order to build up an intimate understanding of the daily movements of his victims.As well as being an expert in covert surveillance, the raider has also shown athletic prowess, scaling high walls and fences while evading detection by sophisticated security systems.Police said he also displays a chilling degree of nonchalance, even when entering a property with multiple occupants. Once inside, he uses a sawn-off shotgun, cable ties and extreme violence in order to force the home owners into giving up their valuables.Video: Terror of one of The Night Watcher’s victims Among the items stolen were a £400,000 diamond tiara and an emerald ring given by Charles II to Louise de Kerouaille, his mistress.Police believe the first raid took place in November 2014, when two women were attacked in their home near Kingswood Golf Club in Surrey and needed treatment in hospital. The Night Watcher is captured on CCTV footage in Maidenhead, BerkshireCredit:Surrey Police/PA Detectives said the extraordinary degree of planning and preparation that goes into each raid suggested he has undergone some form of military training, and have not ruled out that he could be a serving soldier. An 1820 diamond tiara, worth in the region of £400,000 stolen in the break-in at Goodwood HouseCredit:Sussex Police/Solent News & Photo Agency High-value items taken from some of the wealthy homes raided by the Night WatcherCredit:Surrey Police/PA After being bound and gagged, he and his wife lay injured for two hours before a staff member found them and alerted the police. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings.