A dog was left in a hot car parked at a Stroud supermarket on Monday, during the UK’s heatwave.
Shoppers tried to intervene and then contacted police after the owners had returned to the car and left.
Police attended the dog owner’s address and gave words of advice to the owners.
A spokesperson for Gloucestershire Police said: “With temperatures still high please be sensible when it comes to taking your dog out.
“Missing a walk, or taking a later one, has never killed a dog but heatstroke can quickly become fatal.
“If you spot a dog in distress inside a hot car always dial 999.
“We do not recommend forcing entry into a vehicle. If the situation becomes critical and you feel that this is the only option then please speak to one of our call handlers about what you intend to do and why.
“Take photos/videos and gather as much evidence as you can.”
A dog could die in a hot car in as little as 20 minutes, according to the Dogs Trust, and winding down the window is not enough.
In the temperatures seen in Stroud over the last week, dogs need plenty of shade and water and should be walked in the early morning or late evening, according to the Trust.
Tarmac can burn dog’s paws, so owners should check the pavement with their hand for seven seconds before letting their dog walk on it.
You can also use pet-safe sun cream on exposed parts of your dog’s skin.
5 signs your dog has heatstroke
• Panting heavily
• Drooling excessively
• Appears lethargic, drowsy or uncoordinated
For advice and information, including emergency first aid for dogs, visit the RSPCA website.