Cell phone spying software allows a person to gain complete access to your cell phone, including your positioning, text messages, emails and phone conversations. The intruder may even be able to turn on your microphone and listen to your conversations while you are not using the phone. Because of this, it's best to never let someone you don't trust borrow your cell phone, as all it takes to download and install the necessary software on your phone is a few minutes. If you suspect that your phone has been compromised, there are a few different ways to tell.
Check your cell phone bill. If it shows an unusually high number of text messaging or data usage, you may have a spy.
Keep an eye on your phone. If it lights up at random times, even if you aren't using it, that could indicate that someone is checking your position or listening in on your conversations. In addition, if you have a hard time shutting down the phone, or it stays lit up even though it is supposedly powered down, someone else may be using it.
Listen to your phone. When you are on the phone, listen for unusual beeps and clicks or a fuzzy ambient noise.
Feel your phone's battery. If it is warm even though the phone hasn't been in use, it's possible that the phone has been in use, only not by you.
If you believe you have a spy, remove your battery when your phone is not in use.