HUTCHINSON, Kan. (AP) — A pretrial date has been delayed for a 15-year-old central Kansas boy ordered to stand trial as an adult in the fire-related deaths of his mother and sister.

Samuel Vonachen has pleaded not guilty to two counts of premeditated first-degree murder, attempted first-degree murder of his father and aggravated arson. Authorities allege Vonachen used gasoline to ignite his family’s two-story Hutchinson home in September 2013, killing 11-year-old sister Audrey Vonachen and their mother, 47-year-old Karla Jo Vonachen.

His father escaped the burning residence.

The Hutchinson News reports that a pretrial hearing was scheduled for Friday, but was pushed back to Aug. 14 because Vonachen is getting a new lawyer.

Vonachen is scheduled to stand trial Sept. 21.