Bones found at a prehistoric burial site indicate they belonged to victims of an ancient massacre, say scientists.
The Neolithic bones were discovered at Wayland's Smithy
Remains of 14 people were discovered at Wayland's Smithy, near Uffington White Horse, Oxfordshire, in the 1960s.
Latest techniques date the bones at between 3590 BC and 3560 BC, and have led experts to believe the people may have died in a Neolithic Age massacre.
English Heritage carried out the work with the help of Cardiff University and the University of Central Lancashire.
Michael Wysocki of the University of Central Lancashire says the findings suggest the Neolithic Age was more violent than previously thought.
The victims - three of them probably killed by arrows - could have died in a rush for land or livestock, he added.
He said: "We know one person was shot through the lower abdomen because we have found the tiny tip of a flint arrowhead embedded in their pelvic bone.
"We also know that the bodies of two people were scavenged and partially dismembered by dogs or wolves before their remains were buried in the monument.
"All this new evidence suggests that the period between 3625 BC and 3590 BC may have been one of increasing social tension and upheaval."
The research also indicates that the use of Neolithic long barrows was short-lived - and did not take place over hundreds of years as previously thought.
English Heritage radiocarbon dating expert Alex Bayliss said: "With this research, we can now think about the Neolithic period in terms of individuals and communities and make useful and revealing comparisons between their choices and behaviour in the remote past.
"This dating programme demands a revolution in our thinking about prehistory and not just that of early Neolithic burial monuments in southern Britain."