Trophy Skull at the Hopewell Mound Group in Ross County. Human Sacrifice?

The skeleton on the left is flanked by an ocean shell and then a trophy skull that appears to have a copper helmet. What does this signify?  Was this human sacrifice? Was this to be his slave in the afterlife? There just isn't enough information to formulate a hypothesis on this type of burial. More evidence of human sacrifice within the Ohio burial mounds www.nephilimgiants.net : Human Sacrifice is Evident in Ohio's Giants Tombs

The burial was mound # 5 within the enclosure marked "effigy."