Derek Ficik, 26, of Maryland Heights, was charged Tuesday with multiple counts of making a terroristic threat.
According to police, Ficik called Pastor Marc Sikma of Matthais' Lot Church in St. Charles on Sunday and left three threatening messages on his answering machine.
Police said during one of the message, Ficik told Sikma he would burn his church building down.
According to KMOV, police said Ficik, who claimed to practice witchcraft, also told the pastor he would look him directly in the eyes and tell him to pray to God before shooting him in the head.
"He further threatened to burn Christianity and all its followers and (that) he would fill the seas with Christian blood," according to a St. Charles Police probable cause statement.
According to police, all three messages contained graphic language, were sexually explicit and made specific threats.
The recorder of the church captured the phone number of the caller, which led police to Ficik, who had attended the church on Thursday as a guest of a regular attendee.
In addition to witchcraft, Ficik claimed he practiced astral projection. He said demons also told him to do things and he must obey. Ficik also allegedly told police evil and dark things fascinate him.
Ficik is being held in the St. Charles County Jail on $50,000 cash-only bond.