This news is courtesy of a good friend who travels a lot and stays alone at hotels and at home. She saw this while on her trip to the US.
Police in the US recommends a simple safety device called the Super Grip Lock to be placed on your door lock to prevent someone from breaking in or opening your door even if they have a key.
Here’s a video showing how the device works.
If it’s not available in your local hardware store, its available on Amazon.