Quote:
Originally Posted by underscore
^ Based on what we know I would agree.
Here's the route for the flight it could have shadowed to hide from primary radar across India, etc. (going north sounds more likely though, in which case another flight may have worked)

|
you will have to be extremely close to the other aircraft in order to be able to "hide" under it's shadow, especially when you are a 300t aircraft - not a Cessna Baron or Citation that drug runners use
So close it would activate the TCAS (Traffic Collision Avoidance System) on the KLM Aircraft, in which the pilots would call the ground to ask about the other aircraft trailing them. (keep in mind too that the aircraft would show up as a blip on the KLM Aircraft's ND)