My iPhone is stolen and cops have imei number but what if local service is off or gps is off can they caught him ?
The cops can trace the thief if the device is off only if you had activated the 'Find My iPhone' app. If you had not enabled this app, only Apple can help in locating the device using their system. This means you will have to contact them too.
They could CATCH them, yes.
yes they could the cops could tell the phone company to turn on your phone