Find my iPhone app. Somebody stole my iPhone

Okay so somebody stole my iPhone today during school. And I'm desperate & I'm going crazy without it. I wanted to know if Find my iPhone still works if I'm searching for it from another phone, but the device I'm looking for does not have Find my iPhone? But it has the sim activated. And this is kind of a bonus question. But can the police do anything at all about this?

  • Person who stole my phone switched off FIND MY iPHONE So my phone got lost last week tuesday and yesterday i got an email saying find my iphone has been disabled from your device! Also, the person who took my phone plugged it into a computer because i got an email saying a sound was played on your device and that we were unable to put your device on lost mode, because my phone had no connection at all this could only be done through Wi-Fi connection or plugged into a computer! WHAT CAN I DO?
  • Someone stole my dads phone and turned off find my iPhone? So my dad left his phone in line at the grocery store and when he went back the cashier said a couple took it to bring it to costumer service but they never turned it in and turned off find my iPhone. He texted them off another phone to ask them to please bring it back to the costumer service desk and they responded that they were keeping it. Is there any way to track it without find my iPhone or anything legally we can do?
  • Someone one stole my iphone, if they restore it will it delete from find my phone? Someone stole my iphone 5. Either they cut it off or it died either way I can't use the find my iphone app because its cut off. When I locate it, it says its offline but its still listed under devices. If they restored it won't it delete? But I don't know if they wiped it. It just says its offline
  • Please! Somebody stole my iphone 5 I can already guess whoever the thief was has already reset all the settings and took out my sims card and turned off my phone. Is there any way I can still find it?