HOLTS SUMMIT, Mo. -

The murder trial of a Holts Summit man accused of killing his grandmother has been delayed, again.

Attorneys for Ryan Koebel appeared in court Monday and told Judge Kevin Crane that their client is not guilty by reason of insanity. The judge ordered a mental exam for Koebel, therefore delaying his Dec. 11 trial start date.

Koebel is accused of stabbing and shooting Karen Coates in January 2012. Prosecutors also believe he shot at state troopers on Highway 54 shortly after the murder.

He is charged with first-degree murder, four counts of armed criminal action and three counts of assault on a law enforcement officer.