The Butler, Inspecting is Chapter 128 of the Kuroshitsuji manga.
Grell Sutcliff reaps Agni's soul, declaring that he, Arshad Satyendra Iyer, was born on 24 August 1858 and died on 15 November 1889 from multiple knife wounds. Grell adds that they did say that they and Sebastian Michaelis will be meeting again soon.
When Ciel Phantomhive asks Soma Asman Kadar if he is hurt, Soma hits him across the face. After rendering Soma unconscious, Sebastian comments that Soma is understandably confused. A distraught Ciel, seeing Agni's corpse and the state Soma is in, says that he told Soma and Agni to stay out of his business. Then, Ciel composes himself and asserts that he wants an assessment of the situation. Sebastian deduces that something unexpected must have happened since five or ten average humans would not have been able to kill Agni, and that Agni's body is still warm, which means that the attack was recent.
Ciel suggests that they do a sweep of the place. They note that Agni must have been topping up the coal in the hearth and that none of the rooms have been burglarized. Subsequently, they hear a strange noise coming from Ciel's room, and enter it.
To their shock, the words "Who stole the candy from my tummy?" are engraved on the wall. After inferring that the message came from the intruder and that the words appear to be unrelated to Blavat Sky, Sebastian notices that Ciel is deeply agitated. Instead of addressing the issue, Ciel orders Sebastian to have Sieglinde Sullivan tend to Soma's injuries.
When Sebastian lifts Soma, Ciel spots pieces of a photo falling from his hand. Upon realizing what they are, Ciel asks Sebastian for confirmation that he would never lie to him. Sebastian assures him that he does not tell lies, and Ciel is horrified.