Two adults and a child were killed by a grenade thrown into a house in the northern Mexican state of Durango on Friday, according to dpa. The public prosecutor's office said a group of armed attackers had targeted the home. One of the adults who died in the attack was the father of the 3-year-old child who was also killed. The identity of the other victim was not known. Authorities were investigating the motive for the attack in the town of Vicente Guerrero.