Police urge people to call them if they see clear roof during snowy weather

"If anybody notices a sight like this, can you let us know."

Kingsbridge Police shared a photo of a home in the Netherlands that they say is a big sign crime is going on inside.

"If we are lucky enough to have some decent snow over the next few days, and if anybody notices a sight like this, can you let us know," they said alongside the image.

For those who are still non the wiser, the image shows the roof of a house with no snow on, even though the two adjoining homes are coated in the white stuff.

Police say that this is a dead giveaway that someone inside is growing drugs, in particular cannabis.

Cannabis production requires heaters and hot lights to encourage plant growth, but it does mean growers get caught out easily when snow comes and their roof melts first.

The image shared by Kingsbridge Police came from Haarlem near Amsterdam, when the Dutch officers uncovered an illegal farm as a result of the suspicious looking roof.

Forces in the UK are also known to detect drug-growing operations by using thermal imaging cameras in helicopters to see which homes are looking suspiciously hot.