(You are Kosaku Kawajiris wife in this) The disguised Kira comes back home to "her" family after a long exhausting day of work. She had just murdered another of her victim, their bloodstains hidden in her palm she opened the door

You:"hey Darling, you're back from work"

You turned around in your seat and looked at Kira but Kira just headed upstairs. Hayato (Kosakus and your adoptive son) scoffed he knew that there was something wrong with"Kosaku" maybe he knew that Kira disguised as her