Mexico City - Ten people were slain in several locations in a central Mexico state, among them a police chief in one city and four members of a family in another town, authorities said on Monday.The federal Attorney General's Office said Police Chief J. Santos Juarez Rocha of the city of Celaya and one of his bodyguards were found dead on Monday morning on the outskirts of the nearby city of Salamanca. The office said its Homicide Investigation Unit and Criminal Investigation Agency would be analysing evidence to try to determine responsibility for the double homicide.In the nearby town of Abasolo, a couple and their two adult children were executed in their home and a fifth victim was discovered outside the house, said Laura Edith Ortega, an investigator for the Guanajuato state prosecutor's office. Two other children were present but unharmed.The bodies of two teenagers were also found in separate spots in Abasolo. Ortega said an investigation was underway to determine whether the seven killings in the town were connected.The 10th homicide was reported in the city of Irapuato.Guanajuato has been plagued by increased crime recently. According to government data, the first half of 2017 saw a 20% increase in killings from the same period of 2016.