Almost £30,000 worth of damage was caused to vehicles on the Lynn docks at the weekend, police say.
Vandals used a crane to break into the premises on the Bentinck dock sometime between noon on Sunday and 10pm on Monday.
The vehicle was then used to destroy another crane, pictured above, on the site, while five lorries which were also kept in the yard had their headlights smashed and windscreens damaged.
A Norfolk Police spokesman said the cost of the damage had been estimated at more than £29,000.
And PC Jamie Haslam, who is investigating the incident, said: “This is a serious incident, causing a high cost damage to the victim and appears to have been done just for the enjoyment of the persons involved. I would appeal for anyone with any information to get in touch.”
Anyone who witnessed the incident, or who has information about it, is asked to contact Mr Haslam on the non-emergency 101 number (calls 15p).