When you restore a phone, it wipes all data from the device and resets it to factory. However, with the newer iOS, before the device can be activated, it also requires the owner's Apple ID and passcode. If you had Find My iPhone activated, it will not allow the restore until Find My iPhone is turned off, and that requires the Apple ID and passcode as well. More than likely the attempt to restore has rendered the device inoperable, and that, in combination with being powered off, and the SIM being removed is why it is showing off line. Like I said in my first post, with no SIM in the device, it cannot connect to the internet, so it cannot be located on Find My iPhone, so it shows offline.