The spate of burglaries took place at homes in the the W8 area of London between 3 March and 12 April this year.
Stolen possessions include jewellery worth tens of thousands of pounds, cash and foreign currency, vintage watches and £185,000 worth of designer bags by brands like Hermes and Louis Vuitton.
A solitaire emerald-cut diamond platinum engagement ring that belonged to a homeowner’s late mother was also taken from a flat on Palace Gardens Terrace.
“This burglary has made me feel very sad,” they said, explaining that the watch and ring had been in her family for more than 70 years. “The fact that someone came into my house uninvited and rifled through my possessions is distressing.”
Police have described the burglar as “organised and diligent”, waiting until dark to climb into gardens and scale walls and drainpipes before rifling through cupboards and drawers armed with a torch.
They say the man has been targeting properties, located in an area where average house prices are between £2m and £4m, with “great care”.
In another incident, the thief broke into the top floor of a four-storey house, breaking through the window while the family were downstairs having dinner and searching a bedroom while the children were having a bath next door.
He stole a £30,000 rose gold Rolex watch as well as cash and bank cards from the property.
One another occasion the homeowner, who was abroad, checked in on his children and their nanny via cameras in the house and saw the burglar creeping around.
“This type of crime has a huge impact on not only the victims and their families, who no longer feel safe in their own homes, but upon the local community who are worried he will strike again,” Detective Constable Eve Kelly said.
“He is not afraid to break in when families are at home, although I must stress he takes care not to be seen and has not physically harmed anyone.”
The suspect is described as white, between 20 and 40, and of athletic build, and has been pictured wearing a hooded jumper.
Anyone with information can call Kensington and Chelsea police on 020 8246 0122 quoting Operation Redwulf, or call Crimestoppers anonymously on 0800 555 111, or tweet officers at @MetCC.
The Palace Garden Terrace victim is offering a reward of up to £40,000 for the safe return of her mother’s engagement ring and watch. Anyone who can help can contact her directly on 020 3195 3999.