Investigators are digging deep into the background of a would-be assassin in Pennsylvania. And as with most investigations these days, that includes his digital footprint. However, unlocking any suspect's devices can be difficult and expensive, especially if the device maker doesn't help. Earlier in the week, FOX News Rundown host Lisa Bready spoke to retired FBI agent John Iannarelli about how authorities access a suspect's phone, the hurdles they face, and how critical that information can be. He also discussed the legal tug-of-war between law enforcement and phone-makers that occur during investigations.  The conversation was long, and we could not include all of it in our original FOX News Rundown segment. On the FOX News Rundown Extra, you will hear our entire conversation with retired FBI agent John Iannarelli and learn even more about how cell phones can be valuable investigation tools.  Learn more about your ad choices. Visit megaphone.fm/adchoices