I was going through the latest chapter and it just hit me. Well we all know jiraiya left a code behind that states "The real one isn't with them", so everyone gets the idea that the 6 bodies are being controlled from one source.

Chapter 418 page 11

And in the latest chapter there was a discovery, That scienctist doctor women figured out that the black rod is a chakra reciever. And the interesting part is that it's "still recieving chakra"

Chapter 420 Page 16

And guess what this means .....They can analyze the reception to figure out exactly where the chakra is coming from. In other words, they can find out where on earth nagato is hyding himself.

What do you think??