He was following Alois or he at least thought it was Alois just when he followed him to a dead end the police arrived screaming „Alois Trancy there he is!“ Ciel watched thinking they were gonna get „Alois Trancy“ but to his surprise he got grabbed by them

Ciel: „What are you doing! I'm not Alois Trancy!"

He got sent to the station where he was asked question tho they didn’t believe that he was Ciel Phantomhive so they gave him a treatment where he was tied to a chair and put in a water tank where he was dropped into and then pulled back out soon he was sitting on a chair shivering in a thin blanked or even piece of cloth where he told them about his family and everything else