Old iron gates have been stolen from homes in a series of incidents.
Two gates were stolen from homes in Kings Langley - one in Penmans Green between Thursday 16 and Friday 17 October and one from an address in Bucks Hill between Friday 28 and Saturday 29 November.
In another incident a gate was removed from a home in Heronsgate Road, Rickmansworth between Thursday 13 and Friday 14 November.
Steve Jacob from the Rickmansworth neighbourhood police team said: “These items are very expensive and their thefts have left the owners understandably upset.
“We are investigating whether the thefts of these gates are linked, but nevertheless they are very distinctive items and may be taken for a niche market or melted down.
“I would urge anyone who may have seen anything suspicious in the locations on the dates above to call us via the non-emergency number 101.
“Alternatively, if you have been offered gates for sale, whether as a scrap metal dealer or as a member of the public, please call us.”
The price of metal has increased in the last few years, leading to a rise in the theft of catalytic converters.