He was an older hand at this game than the two foreign agents.

"I just had a warning that he is a foreign agent."

That is the agency's standard practice when dealing with potential foreign agents.

This might happen in a network where the foreign agent has not been deployed yet.

"He's a dangerous foreign agent and we saw him enter this club through the side door!"

Let us suppose, for example, that he had been approached by some foreign agent.

Their whole purpose is to make contact with other foreign agents so they can get intel.

The rest are pawns in the hands of foreign agents.

He would naturally have made an appointment with the foreign agent and kept his evening clear.

Which means he is the citizen of another country, a foreign agent.