[For a moment, he seems surprised that it isn't perfectly obvious.

There's the usual Sherlock.]

Moriarty.

I told you-- he planted that idea in your head.

[Still bordering on almost gleeful here, even if there's a drive to his words.]

I was looking for someone experienced passing information to him. Even unknowingly. But a rookie--

[He almost smiles. It's a relief, in a way. To know.]

Best way to keep him close to Lestrade. Ready to strike. He'd keep an eye on anyone new. Especially who needed that sort of influence.

Once again, the planning is absolutely elegant. [...Probably not good to sound almost like you have a crush, Sherlock.]