Criminals are suspected of using some sort of tank after hundreds of litres of oil were stolen from a number of Co Armagh homes.
Police said a number of homes in the Ballyoran Heights area of Portadown were targeted over Christmas.
And such was the scale of theft, the PSNI believe a tank may have been used during the theft.
A PSNI spokesperson said: “The warm and friendly festive cheer was somewhat lacking in Ballyoran Heights by one particular criminal or set of criminals who took the opportunity to steal oil from a couple of houses.
“At some point between the 20th and the 29th December, as much as several hundred litres have gone missing.
“This would have required some sort of tank to remove, so if you saw anyone acting suspiciously in the area over Christmas, please call us on 101. The reference number is 936 of 29/12/18.
“Oil isn’t cheap, and it’s a particularly callous time of the year to target people. If you know something, speak up. You can even call Crimestoppers anonymously on 0800 555 111.”
Deputy Lord Mayor of Armagh, Banbridge and Craigavon Council, Cllr Paul Duffy condemned the thefts.
“These thefts have put a number off families under financial stress and has dampened the Christmas spirit knowing their property was trespassed upon and oil stolen,” said the Sinn Fein Cllr.
He urge people to keep an eye on next door neighbours. “Don’t be afraid to takes picture of tankers in a drive if you have any doubts or contact the PSNI.”