S1E756 : The Tragedy of the Red Woman (Revenge)

A search is conducted they don't find any knife-like objects or wigs. A woman is seen lurking outside again. The group checks some pictures which point to the red hints of all the previous 'pranks'. In one the pictures, Yui points out that on the day she was found she was wearing a red coat. She notices the ones who found the knife 3 years ago were Kansuke Yamato and Taka'aki Morofushi, while they were still attending police academy. Morofushi was sure that the bones which were found belonged to the red woman, while Yamato refused to accept it.