Seven vehicles belonging to a group of charity workers have been targeted by vandals.
Between 8.10pm and 11.40pm on Friday, the volunteers from the Derbyshire Bat Conservation Group returned to their vehicles to find that their tyres had been slashed.
The vehicles, including a Peugeot van, a Citroen Berlingo and a Vauxhall Combo, were parked in a lay-by on Salters Lane, Matlock.
Police want to hear from anyone who might have seen people acting suspiciously around the vehicles between those times.
Witnesses or anyone with information should call Derbyshire police on 101, quoting crime reference number 40758/14. Alternatively, call Crimestoppers on 0800 555 111.