Archaeologyfag here, without knowing how old they are it's difficult. Looks like a couple of these people were tortured or beaten judging by the twisted ribcage of the 1st photo. To be honest it looks like they were dropped from an airplane or tall building. The skulls on the right look like child skulls but the teeth look fully developed. The frontal piece of skull looks like it was removed and stitched back on. Maybe some sort of ceremony of death?