Det Sgt Peter Ritson says there was no evidence of a cause of death.
He said the field where Becky's remains were found was a hard soil. She was buried in only 8 inches of soil.
The Oxfordshire coroner Darren Salter recorded a narrative verdict.
On the available evidence its very likely that her death was unnatural and violent. At an unknown location at the end of 2002 or early 2003. “