Kelvin is Helen's uncle and the villain of The Comfortable Search of the Secret Phantom.
In 11:00 PM before the end of the day I questioned a waiter about his whereabouts and he says that he lives himself in Hammett Square and tell me why so I'm going out quickly to talk to him and I reached his house on 12:00 AM the next day and I talk him about his alibi that says he was drinking with Gustav the Bartender but in next hour I am talking to check his alibi but says "No" because he was tough man to miss so that means I have 100% that Kelvin Rittenhouse is the killer so I go to Rudolph Keane about the proof that he was murderer so the answer was incriminating and the truth is revealed when Rudolph Keane once confided to him that Kelvin was planning to kill her and he realised once he was serious, Rudolph told Kelvin to get a hold of himself. Rudolph thought Kelvin finally talk much out of it, but he beginning to think he went through his crazy plan. I search case about the motive of Kelvin. I send some information from the Fact Checker but only I know is the address. I search case about the motive of Kelvin. I send some information from the Hospital and I see the truth. Revealed to be about he admitted his symptoms of extreme irritability and hypertension. Doctor prescibe sedatives for the problem, and left an interesting role on the patient's client and reason why of Kelvin's condition was a intense and barely rage. Kelvin was extremely angry with somebody named Helen and that anger was causing his physical symptoms so his Motive is Hated Victim. According to Rudolph Keane he was talking to Kelvin Rittenhouse about her rage to Helen Keane that cause of killing her. and I watch the case file and skips 1 hour after watching it and 6:00 AM I confront him then accuse and I tell him the truth. Then he confess about his rage of her that was her selfish action to him.