Death Note

[adithya]

So, to anyone who's seen the anime. I'm rewatching it for the umpteenth time, and yet I don't understand how Near knew it was Mikami. If anybody has an explanation, I suggest you clear me of my doubts.

[Xendrus...]

Near knew that there was another person who was aiding Kira, and that Kira and this other person were contacting each other through Kiyomi Takada. After Near established this, he saw a video of Teru and Kiyomi Takada on some show talking about Kira. He put two and two together and connected the dots, placing Teru as the "X-Kira".