Genocide in pre-Columbian America?

Scientists are examining seven skeletons—five adults, one child, and an infant—discovered two years ago in a canyon in New Mexico. Ascribed to the small and little-known Gallina culture, the skeletons have something besides heritage in common. All show the marks of violent deaths - axe blows, broken bones, shattered skulls. The skeletons presumably were left there before the complete disappearance of the Gallina sometime around AD 1275. American archaeologist Tony Largaespada told an interviewer that almost all the Gallina people ever found were murdered. "[Someone] was just killing them, case after case, every single time." It's one more mystery from ancient America.