Takahashi makes his first appearance in episode 2. He is standing in the same room as Toue and Sei and informs them on visual images of Aoba and Noiz's Rhyme fight.

In episode 3, Takahashi is giving Toue more information on the samples being taken from the outside and the drug's side-effects (the Morphine ambushes). Later, he is seen in his own car in the Old Resident's District. Tae appears to be in the back seat and Takahashi asks her, "So he was alive?", referring to Aoba. Tae merely looks down as Takahashi smiles.

Note: Takahashi only appears in the anime.

(Source: DRAMAtical Murder Wiki)