Fuel was stolen from four cars parked in a business park over the festive period.
Hertfordshire Constabulary are investigating after fuel was stolen from inside four vehicles parked on Caxton Way, Watford, over the Christmas and New Year holiday period.
At this stage, it is believe the fuel was stolen at some point from 5.30am on December 22 and 11am on January 2, when the theft was reported.
The cars affected were all Vauxhall Corsas: two black, one silver and one grey.
The cars have now been taken back to Borehamwood.
Anyone with information should contact Hertfordshire Constabulary on 101, quoting crime reference C1/18/46.