Burglars who ransacked a house in Oxhey and stole more than 70 items of jewellery are still at large.
Hertfordshire Constabulary said the break-in happened at a property in Eastbury Road on December 10, between 10.40am and 2.30pm.
Burglars smashed the glass to a side door to gain entry. Samsung Galaxy Tablets and money were also taken.
Paul Walling, home-owner, said: "Our daughter came home before us and found the house had been broken in to.
"It’s very unusual for the house to be unoccupied so we think someone must have been watching the place.
"She saw the back gate was open and there were some tools by the back door. I told her to get away from there and call the police in case they were still in the house.
"We had three police cars turn up within minutes and went over the house for fingerprints for about two hours.
"We had to climb over everything because there was stuff all over the floor. The burglars were remarkably careful, hardly anything was broken. They clearly knew what they wanted.
"Working out what has been taken is an absolute nightmare. Every drawer and cupboard has been pulled out, stuff has been moved around.
"It was the sentimental stuff, the mother’s wedding ring, stuff I bought her from Africa, they are replaceable but it won’t be the same.
"Nobody got injured and that is what is important."
Assistant investigator Elaine Counsell from Watford police station said: "A significant amount of jewellery was taken from the property and the victim would like to see this returned.
"If you have seen a necklace similar to the one pictured or know of its current whereabouts then please call with information.
"I would also like to speak with anyone who may have any information about the offenders involved."
Anyone with information can telephone AI Counsell on 01923 472939, via 101 quoting crime reference number C1/13/5581.