TULSA, OK -- A former school teacher facing a murder charge plans to use insanity as a defense.

John Kastner's attorney announced his defense plans Wednesday. The judge told the attorney to file the proper paperwork by Monday or the trial will go on as scheduled January 4th.

If the paperwork is filed, the trial could be delayed to give prosecutors time to have experts evaulate Kastner.

Kastner used to teach at Webster high school and is accused of murdering his wife Lori and making it look like a botched home invasion robbery in June of 2008.