This case study introduces the analysis of perimortem injuries found in the skull of a male individual with artificial cranial deformation, from the cemetery Tarapacá 40, associated to the habita-tional site Caserones 1. The skull exhibited traumatic injuries, three corresponding to sharp force trauma, one to a blunt force trauma and a possible fifth also originated by a blunt force object. It is worth to mention that out of 51 individuals recovered from Tarapaca, only this one exhibited perimortem injuries. Based on the injuries it is argued that the individual was attacked with a stone axe and a garrote; concluding that violent confrontations among individuals from Formative period (1000 b.C.–900 d.C.) might obey to stress factors originated from social, economic and demographic changes of the abovementioned period.