Cydia app iGotYa allows iPhone owners to find out the person who used their iPhone in their absence. The app uses iPhone’s front facing camera and GPS coordinate to record the information and then sends the information to the owner’s email.
iGotYa requires the iPhone to be protected with an unlock code as it starts working only when the user enters the wrong unlock code.
iGotYa will allow you to take a picture of the person trying to use your phone (using front-facing camera) and get the location where your iPhone is at. You will need to protect your iPhone with a unlock code and iGotYa will do the rest. if the unlock code is entered wrong then iGotYa will take a picture and the location of your iPhone silently and send it to your email. You can also allow access to the iPhone with a wrong code entered but all your personal data (SMS, Call History, Web History, Mail, etc) will be hidden.
iGotYa is available via ModMyi repo and costs $4.99 to download and install.