Scientists have unravelled the mystery surrounding 100 burned and bashed bones
DETECTIVES have solved the "world's oldest cold case" as battered human bones give clues to seven brutal deaths almost 6,000 years ago.
Archaeologists discovered a scene of mass death in 2004 with nearly 100 pieces of human bone at the site of a prehistoric house.
The dwelling had been in the ancient settlement of Kosenivka, about 115 miles south of the Ukrainian capital Kyiv.
The bones from most of the Stone Age skeletons were charred and burned, and two of the skulls had been brutally caved in.
The skeletons belonged to at least seven people: two children, one teenager and four adults.
Interestingly, the only four skeletons inside the house were scorched, whilst the three found outside were not.
Initially, it had been presumed that the deaths were accidental - perhaps as a result of a house fire.
However, the realisation that two of the adults suffered violent head trauma just before their deaths sparked a 5,700-year forensic investigation.
The mystery thickened when radiocarbon dating determined that six of the people, possibly a family, died between 3690 and 3620 BC, whilst the seventh - an unburnt adult - died around 130 years later.
Only the skull of this mystery seventh person was present.
Researchers studied closely the fracture patterns and discolouration displayed by the bones to deduce all they could about the last moments of the Stone Age people.
The team concluded that the people inside had been burned to death, unable to escape the flames, whilst the others managed to stagger outside but later succumbed to smoke inhalation.
The brutal head injuries, however, remain the subject of speculation.
Katharina Fuchs, a researcher at Kiel University in Germany, suggested that the death scene involved someone "killing the people in the house, leaving their corpses, and setting the house on fire".
The study paper also believes that the house and bodies were completely covered with soil soon after the tragedy, and then the skull of someone else was placed on top a century later.
The authors believe that the final skull could have been placed on top of the site as part of a deliberate ritual.
Jordan Karsten, an archeologist at the University of Wisconsin, told Live Science: "It seems reasonable that the individuals recovered from Kosenivka were killed during a raid and that their house was lit on fire during the conflict."
"Previous explanations [for houses burned in this period] have focused on ritual house destruction through intentional burning, but these results suggest that intergroup conflict might better fit the data."
The group who died was part of the "Cucutine-Trypillia" society, thought to be the oldest civilisation in Europe.
People who research this era know the people as the "missing dead", due to the lack of graves, bodies and burials that have been unearthed.
The Kosenivka "mega-settlement" consisted of public buildings and family homes, many of which were deliberately burned down when people left.
It is unusual, however, to find bones in the burned-out houses, which is why this case surprised scientists so much.