Where? The only thing he expected them not to know is the real extent of his power i.e. they knew he was dangerous, so they'd send their best, but they had no idea just how very dangerous - if they did, they likely would give up altogether. This turned out to be true, they came and they failed. He also mentioned that were they able to capture him, they'd either kill him, or make him manufacture the weapons, so it's obvious he expected them to know pretty much all about his previous visit to the country.
If they know about his work with Kaushman and the fact that he wandered around the world for decades with potentially ultra-secret knowledge, then this all becomes moot. What's the point of him coming to work to their detriment now? He could have taken away the advantage that justifies all this conspiracy decades ago, by sharing his knowlede with their enemies. They know for a fact that he didn't, so whatever his goals are now, they are not in direct opposition to the country. Besides, if they were really worried about him potentially working for the enemy, then it makes far more sense to first contact him and see what he's after. That opens up possibilities, like offering a more expedient way to get him what he wants in exchange for his help or at the very least, an opportunity to get at his handlers. Even if they were successful at killing him, that thread is severed.