The mother of a 6-year-old Minnesota boy has been arrested after his body was found in the trunk of her car Friday, the Star Tribune reports. The grisly discovery was reportedly made in Mound, Minnesota, after police were notified of a car driving on a tire rim with the glass smashed out of the back window. Once police approached the vehicle, they reportedly discovered blood and the boy’s body in the back. The driver and a passenger, who were not identified, were both taken into custody. According to relatives of the deceased child cited by the newspaper, the boy’s father, Tory Hart, had been trying to reclaim custody of his son when he was discovered dead. The family has criticized local social workers for allowing the boy to be returned to his mother from foster care, the Star Tribune reports. “This county failed this child big time,” Nikita Kronberg, a relative of the mother who once fostered the child, said. Hart’s fiancée, Josie Josephson, said Hart “expressed a lot of concern” for his son, adding that the child “was loved by everyone who met him.”