Doubt

Doubt  (疑う, Utagau) is the tenth episode in the Japanese anime Death Note.

Synopsis
L, in a bid to profile Light's behaviour, challenges him to a game of tennis. Afterwards, L asks him some questions regarding the Kira case, and if he would be willing to help in the Kira investigation. The two then receive news that Soichiro Yagami has had a heart attack and is in hospital. Light promises an oath to his father that he will make sure Kira is caught and executed for making him suffer. On the way out, L confronts and scrutinises Light, still uncertain if he is or is not Kira. Light attempts another bluff and demands to be placed in a prison cell without television for one month to prove his innocence. For now L is satisfied but curious that Light offers this proposition. Meanwhile a television station, Sakura TV, receives audio tapes from an anonymous person claiming to be Kira.