All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu 'alayhi wa sallam, is His slave and Messenger.
The mere mention of murder in novels and stories, or watching murder scenes in movies and the like, does not necessarily mean that you are pleased with what Allah prohibited or that you consider it to be good.
Moreover, being pleased with the prohibitions that are less grave than Kufr (disbelief) – like murder, for example – is undoubtedly not considered Kufr.
Rather, being pleased with Kufr is considered Kufr only when accompanied with regarding it as good, not when accompanied with regarding it as ugly. Haashiyat Ash-Shihaab Al-Khafaaji ‘ala Tafseer Al-Baydhaawi reads: “It was said in Al-Kashf: The scholars of Transoxania said, ‘Being pleased with Kufr while considering it ugly is not Kufr; rather, it is Kufr when accompanied by considering it good. Allah, The Exalted, Says about Prophet Moosa (Moses), may Allah exalt his mention, (what means): {Our Lord, obliterate their wealth and harden their hearts so that they will not believe until they see the painful punishment.} [Quran 10:88] He meant (with his supplication against them) that Allah, The Almighty, increases their punishment.” [End of quote]
We advise you to keep away from whisperings and pay no attention to them at all.
Allah Knows best.