Won't Forgive Even One Millimetre (1) Meitantei Conan : Season 1 Episode 675

The detective boys are invited by a couple for a barbecue. After eating the husband was looking for his phone get engaged into a quarrel with his wife. Meanwhile, Ayumi finds the cellphone and goes to return it to the couple finding the wife trying to kill her husband. As the detective boys go into the house they find the wife was lying on the ground stabbed in the heart.