AUGUSTA -- A double homicide trial will begin next month for a 22-year-old man charged with killing a former high school classmate and then fatally stabbing his own father six days later.

John A. Okie's trial is scheduled to begin Dec. 8 in Kennebec County Superior Court before Justice Joseph Jabar.

The former prep school student is charged with murder in the death of 19-year-old Alexandra "Aleigh" Mills, whose body was found July 10, 2007, in her family's home in Wayne. She and Okie were former classmates at Kents Hill School in Readfield.

He is also charged with killing his father, 59-year-old John S. Okie, in his home in Newcastle following an argument. The younger Okie is accused of repeatedly stabbing his father after the two argued in their home, according to a police affidavit.

"As of this time, we're anticipating a jury trial," said Deputy Attorney General William Stokes, who heads the criminal division of the state attorney general's office.

Okie has been held without bail since his arrest the day after his father's murder.

He has undergone psychological evaluations while in custody, and has been found to be competent to stand trial. At his arraignment in September 2007, he pleaded not guilty and not guilty by reason of mental disease or defect to both charges.

Prosecutors at the trial will be Lisa Marchese and Andrew Benson, both assistant attorneys general.

The trial is expected to last a couple of weeks.