GREAT FALLS, Mont. (AP) — The Montana Supreme Court has ruled a Great Falls man must testify at his deliberate homicide trial if he wants to argue he shot a Fairfield man in self-defense.

Tuesday's ruling came in the case of Martin Lau, who is charged in the August 2012 death of Don Kline at the home Kline shared with Susan Pfeifer.

The Great Falls Tribune reports ( ) the justices ruled that Lau had to testify in order to argue that he shot Kline because Kline was threatening both he and Pfeifer and that Pfeifer told him Kline had been abusing her.

Lau's attorney, Kenneth Olson, had sought to make the self-defense claim by introducing into evidence the prepared statement Lau provided investigators. Prosecutors and the Supreme Court said the statement is inadmissible hearsay unless prosecutors could question Lau under oath.