Thieves have syphoned around 130 gallons of fuel from a lorry parked on a lay-by on the A46 in Lincoln.
The incident happened between 7pm on February 18 and 7am on February 19.
A Volvo HGV lorry was parked in a southbound lay-by on the bypass, between Skellingthorpe Roundabout and Doddington Road.
The offender(s) forced open the locked fuel cap and syphoned some 130 gallons (around 490 litres) of diesel, worth around £650.
Lincolnshire Police are appealing for anyone who saw or heard anything suspicious in this area between these times to call them on 101 quoting incident 24 of 19/02/2014.