MARYSVILLE, Ill. - Police said they still were trying to learn the motive in the shooting death of a Marysville, Ill., pastor in front of his congregation during a service.

Fred Winters, the pastor of the First Baptist Church, was shot and killed during a morning service Sunday by a man who then drew a knife before two parishioners subdued him, CNN reported Monday. The attacker and two parishioners suffered knife wounds in the attack, authorities said.

The man entered the church during the 8 a.m. service and walked up to the pulpit, apparently exchanging words with Winters before firing four shots, Illinois State Police Director Larry Trent said.

"The only thing we know is that the suspect said something to the pastor and the pastor said something back to him -- we don't know what that was," Trent said in a briefing after the shooting at the St. Louis-area church.

The First Baptist Church congregation had a disaster plan in case an incident such as Sunday's attack occurred, police said.

Earlier reports indicated the man may have turned the knife on himself, but Trent said that was not confirmed.

"When he was tackled by two of the members, we don't know whether he fell on the knife, injuring himself at the time, or whether (his injury) was self-inflicted during the struggle," Trent said.

A St. Louis University Hospital spokeswoman told CNN three men, including the suspect, were brought to the hospital for treatment.

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