Their son Richard Leakey dug both skulls a decade later. He thinks skull owners have been the earliest users of oldowan tools, which are found in the same area. However, the coexistence of fossil homo with tools and skull paranthropus calling the idea was questionable. Many of the other fossil animal mammals excavated with paranthropus fossils have evidence of a meat shop on their bones. The newly found bones suggest those owners also meet the final violence.