The jury in the trial of the man accused of strangling Ffion Wyn Roberts has been warned they must consider the case with a cool head.
Judge Mr Justice Lloyd-Jones began summing up at Caernarfon Crown Court, almost exactly a year after the 22-year-old's body was found in a drainage ditch at Porthmadog, Gwynedd.
He said Iestyn Davies, 54, of Porthmadog, who denies murder, had nothing to prove.
The trial continues.
The judge said: "It's for the prosecution to establish the guilt of the defendant. He has to prove nothing."
The prosecution has said the case against Mr Davies, a wool packer, was "overwhelming."
The defence argue there is a gap in the Crown Prosecution's case and he did not kill Ms Roberts.
Defending barrister, Patrick Harrington QC, has told the jury the prosecution had to prove her violent brother was not the killer.