HASTINGS, Neb. (AP) — A 24-year-old man has been found guilty of helping his mother stab her boyfriend’s 68-year-old mother.

Jurors found Andrew J. Casterline of Guide Rock guilty on Thursday of first-degree murder, use of a deadly weapon to commit a felony and burglary in the death of Virginia Barone.

Casterline’s mother, Shelley, pleaded guilty in March to second-degree murder. She’ll be sentenced later this month.

Barone’s body was found partially covered by boards in her home last fall. Prosecutors argued Andrew Casterline helped his mother attack Barone, who was stabbed twice in the back and 20 times in the chest and torso.

Shelley Casterline says she had a bad relationship with Barone. She says they were arguing before Barone’s death.