A photo on Facebook has gone viral after a woman posted a photo of her windshield on the social media site.

The photo shows a small white rectangular sticker on the top corner of her windshield. She doesn't know how it got there and she says several other colleagues, all females, had the same thing posted on their car.

Police have been notified of this and are looking into the matter. It was noted in the post that some tracking devices look similar to these, thus they want you to be aware of such.

If you happen to see such on your car it is probably best to remove it and notify police. As always, stay alert and never let your guard down.