An Illinois landlord convicted of fatally stabbing a 6-year-old Palestinian American boy and severely wounding his mother in a hate crime has died in custody, just months after he was sentenced to 53 years in prison.

Three months ago, Joseph Czuba was sentenced to 53 years behind bars for the attack. He was found guilty in February of murder, attempted murder and hate-crime charges in the death of Wadee Alfayoumi and the wounding of the boy’s mother, Hanan Shaheen.

Joseph Czuba, 73, died Thursday while in the custody of the Illinois Department of Corrections, said Kevin Hedemark, sheriff’s office spokesperson.