An air ambulance trust has posted an open message on Twitter to the "idiot in Devizes" who shone a laser at its helicopter as it prepared to land.
The post from the Wiltshire Air Ambulance, which appeared on the micro-blogging site on Tuesday, said the perpetrator had "no idea how dangerous that was".
They wrote: "To the idiot in Devizes who decided to laser the aircraft while we were in the orbit to land you have no idea how dangerous that was."
They later added: "All OK just very angry at the stupidity of the person who done it."
A Wiltshire Police spokesman said: "It's dangerous and could have very serious consequences not only for the helicopter crew but also for the patients they may be trying to reach. Police are making enquiries into this incident."