A RESPECTED home security company has issued a warning to all property owners in Spain.
According to Prosegur, burglars are marking people’s front doors with a variety of signals, indicating what type of target they are.
If you see any symbol etched into your door you are advised to call the police immediately, as it means you are likely being watched by thieves.
The symbols are typically very small and are made with chalk.
Prosegur’s key says an ‘X’ indicates that the owners are away on holiday, while an ‘X’ inside a circle means they are on vacation but will be back soon.
Meanwhile, an ‘M’ means the homes are vacant in the mornings, while a ‘W’ means they are empty at night.
A capital D that is underlined, meanwhile, means that the house or apartment is prime for burglarising on Sundays.
If you see a ‘7’ and ‘8’ next to each other, with each number in a circle, that means the property is free during the months of July and August.
A triangle indicates that the home has already been robbed, while a circle on its own warns of police nearby.

A series of other symbols warn of dogs, children in the home and whether or not the home is easy to rob – and even if the owner is disabled.
The chilling code suggests that robbery gangs are watching their targets for some time before deciding to strike.
In addition to drawings, thieves may leave other signs, such as faint threads of glue, adhesive strips, or pieces of plastic attached to doors to check whether the occupants have left the house.
If you come home to find any of the above, don’t touch anything, don’t erase the marks (if they’re made with chalk or something similar), take photographs, and call the police immediately.