Thieves stole a satellite navigation system from an ambulance in Manchester, while the crew helped a patient. It happened as the emergency vehicle was parked on Cobden Street in Blackley on Saturday afternoon.
Greater Manchester Police criticised the theft, as the system helps ambulance drivers get to members of the public more quickly.
Anyone with any information about the theft is urged to contact police or Crimestoppers anonymously.
A police spokesman said: "These are particularly galling crimes because ambulance service staff are trying to serve members of the public and do their job as efficiently and swiftly as possible.
"This is a particularly selfish and reckless incident the thieves stole the sat nav system whilst the ambulance crew was dealing with a patient.
"The sat nav systems speed up the time ambulance drivers can respond to emergency call outs and they are a vital piece of equipment."