Thieves in Londonderry are using sophisticated equipment, including tankers, to steal home heating oil.
The police have warned householders to be on their guard after a spate of oil thefts in the city.
One pensioner, Majella Doherty, had her oil stolen days after getting her tank filled.
The 62-year-old used her winter fuel payment to help pay for more than 600 litres of oil which she had hoped would last the winter.
"I felt awful to think that a thief came in my gate. If they had come and knocked at my door I would have give it to them, but don't steal it," she said.
"It made you feel awful to think that somebody would come into your home and steal oil. But I'm not the only one."