Liu Yongbiao murdered four person and soon related it in his book, called "The guilty secret".
There ir no a better inspiration for a book or a movie that the reality, and as we all know, the reality is always a lot more surprising that the fiction.
The famous chinese writer, Liu Yongbiao, is arrested for committing a crime 22 years ago, and as a confession, has written about this in a book.
The story:
The night of 29th of november of 1995, four person were murdered by a crowd in a pension of the Huzhou city, the west province of Zhejiang.
To rob one of the guests, they beat him 'till death, and to hide their crime, they also killed the couple that were with him, and also his grandchild, of 13 years old.
At the beginning, there were two clients of the pension being suspicious, they were registered the same night the crime were committed, from the province of Anhui. One of the cause was their marked accent. By this time, there was not obligated to be registered with the identity card, for that reason the receptionist can't say much about their real identity.

More that two decades soon, as related in "China Daily", there were new proves and analizes of DNA and fingerprints in 15 provinces, came to the detention of Liu Yongbiao, and his accomplice, of 64 years old, called Wang.
-"I was waiting for you all this time" with these words, the writer recieved the police in his house, to arrest him.
Nobody, includes his wife and family, known about the crime.
He admitted his crime in a video, and with this he can give his inspiration a step in a prison.