WILLITS (AP) — A Northern California man accused of killing his 84-year-old grandfather by dragging him behind a pickup truck for nearly six miles will be sentenced Nov. 14 for first-degree murder.

The Santa Rosa Press Democrat reported Monday that a judge has held 24-year-old Kenneth Wilkinson to a plea agreement made in April. Wilkinson had sought to withdraw his guilty plea, saying he was inadequately represented.

Judge John Behnke said there was no basis for a withdrawal.

Authorities were called to a Willits-area home in March 2013 after family members reported Richard Mel Wilkinson missing. Deputies ultimately discovered a trail of blood and body parts leading to his body, which was found in a ravine.

Public Defender Linda Thompson has said the younger Wilkinson was impaired by drugs and suffered from mental health problems.