A re-examination of 46 skulls from servants' graves at Umm el-Qa'ab, the royal cemetery near Abydos in Egypt dating to around 3,000BC, found that 18 showed potentially lethal injuries, suggesting retainers of early First Dynasty rulers may have been killed when their kings died. The study, by Roselyn Campbell of Purdue University in the US and published in Frontiers in Environmental Archaeology, is the first to analyse remains from the tombs themselves, resolving a century-old debate begun when Flinders Petrie excavated the graves in the 1920s and found no obvious trauma. Campbell cautions that the sample is small and that skulls without injuries cannot be assumed to be sacrifices, but outside experts such as Salima Ikram and Dawn McCormack say the findings are plausible and fit patterns seen in other ancient cultures; the practice appears to have faded by the Second Dynasty, when statuettes replaced people.