Police are investigating two incidents where a driver made off before paying for their fuel.
They happened at the Tesco Express petrol station in High Road, Bushey Heath, at 6.20pm on March 3 and the second at 6.30pm on March 10.
Both times, more than £70 worth of diesel was filled.
Officers have released photos of a man they are hoping can help as part of their enquiries.
PC Gerard Handscombe said: “I am keen to identify and speak to the man pictured as we believe he was in the area around the time of the incidents and may have further information that could assist our investigation.”
If you have any information, contact PC Handscombe at gerard.handscombe@herts.pnn.police.uk quoting crime reference 41/20422/19.
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