Lyndon ? A former Missouri city official charged in the slayings of four family members is asking a Kansas court to waive his preliminary hearing so his young son can be spared the trauma of testifying.

James Kraig Kahler, of Meriden, Kan., faces four capital murder charges in the fatal shootings of his estranged wife, their two teenage daughters and the wife’s grandmother in Nov. 28, 2009, in Burlingame, Kan. The son, Sean Kahler, who was 10 at the time, was not injured and fled from his great-grandmother’s home.

In a document mailed Monday, Kahler said he was willing to give up his right to the preliminary hearing to protect his son. The hearing is scheduled for Dec. 21-22 in Osage County Court in Lyndon.

However, the Kansas Attorney General’s office said in a response filed Tuesday that the hearing should be held because the prosecution also has a right to the proceeding, The Topeka Capital-Journal reported.

Kahler’s attorney, Thomas Haney, says the law that allows the state to demand a preliminary hearing when the defendant wishes to waive it is unconstitutional. And he argued that even if the statute is constitutional, there isn’t a legal reason to conduct the preliminary hearing in this case.

“To traumatize an 11-year-old child is uncalled for and serves no useful purpose,” Haney wrote, saying he hoped to spare the boy the “stress and emotional trauma” of testifying.

Assistant Attorney General Barry Disney said in his court filing that state law requires a waiver from both the prosecution and defense before the magistrate can order the defendant to be bound over for trial.

The defense contention that the statute is unconstitutional is “without merit,” the prosecution filing said.

In May, Magistrate Jon Stephen Jones ruled that the boy would testify via a closed-circuit TV during his father’s preliminary hearing.

Kahler is charged with killing his wife, Karen Kahler; their two daughters, Emily, 18, and Lauren, 16; and Karen Kahler’s grandmother, Dorothy Wight. Karen Kahler had filed for divorce in January 2009. Karen Kahler, the two daughters and the son lived in Columbia, Mo.

Kahler is the former director of the Columbia Water and Light Department. He was living in Meriden at the time of the killings.