A free app for Android, by FishingNet.

Hidden Eye – intruder selfie is a useful app that allows you to easily see who has tried to access your phone without your authorization. The app will take pictures of anyone who tries to access your phone with the wrong PIN, pattern, or password. The pictures will be saved in a folder on your device, so you can easily view them later and decide what to do about them.

The app works as follows:

You need to first set up the app.

Then, you need to select the snooper that you want to see.

Then, you need to enter the correct PIN, pattern, or password.