Catching the Spies?

Chris's thoughts were disturbed by the noise that came from the building where the spies built their hideout. He was thinking of a way to make them leave the nest so that he could catch them and luck would have it, they came out on their own.

Chris didn't waste a second and immediately placed trackers on all of them. It was a busy day and even though they had his description, he easily blended with the people, enough to place the trackers.

"Ah, I was right. There are more than three which the intelligence suggested", Chris thought. He has now had to watch them to know who the boss is.

The best time for the spies to leave would have been at night and if they came out at night, it wouldn't have been easy for Chris to place trackers on them. Moreover, he wouldn't have learned that there were more than three of them.