Why couldn't Ibarra find his father's grave?

In Chapter 13, Ibarra arrives at the cemetery, in search of his father’s grave. However, upon arriving where he thinks his father is buried, he can’t find a cross marking the grave. He talks to a gravedigger, who says that he burned the cross because the head priest told him to, and that he was also told to dig up the body and bury it in the Chinese cemetery instead.