Ffion Wyn Roberts murder suspect 'dumped evidence'
A murder suspect dumped incriminating evidence at a sluice gate after killing 22-year-old care worker Ffion Wyn Roberts, a court has heard.
The tracksuit bottoms, a training shoe and the victim's handbag were found because they got lodged in the sluice mechanism.
Factory worker Iestyn Davies, 54, from Porthmadog, denies the murder of Ms Roberts in the town in April 2010.
The case at Caernarfon Crown Court continues.
The court heard that the defendant said: "This is ridiculous" when he was arrested.
Elwen Evans QC, prosecuting, said he also made a series of "no comment" replies when questions were put to him.
He told police that he had been moving from address to address, sometimes staying with friends and in rented flats or a tent on the beach.
When it was put to him that he had killed Ms Roberts it is alleged he smiled.
Asked why he was smiling, he said it was because he "hadn't done it," the court heard.
The prosecution said CCTV images showed Mr Davies walking his dog in the early hours of 10 April.
She said Ms Roberts had been assaulted, strangled and drowned in a water drainage ditch which runs through the Gwynedd town.
The victim's mother, Bethan Roberts, sobbed in the public seats and at one point left the courtroom in tears.
The court heard police had carried out a detailed inquiry building up the case piece-by-piece and step-by-step, discounting some lines of inquiry, leading to Mr Davies being identified as the killer.
Evidence included DNA, fibre, soil and plastic analysis, printing, pathology and a whole range of scientific expertise.
"The evidence establishes an overwhelming case against Iestyn Davies which tied him in with the knot in the scarf used to strangle Ffion," said Ms Evans.
There is also evidence to link him with tears in her clothes and to her handbag, she said.
CCTV images also showed the movements of the victim and Mr Davies, she added.
It is alleged that after killing her Mr Davies went home to his flat, changed some of his clothing and went to get rid of the evidence, including the tracksuit bottoms and trainer, at the sluice gate.
Images caught on CCTV showed his clothing before and after, she said.
Ms Roberts had been caught on camera on the way home after leaving the Union pub at Tremadog at 0400 GMT, under the influence of drink.
It is thought she was killed some time during a half-hour period, the attack taking place in an alleyway near her home.
A man living nearby had heard noise at 0440 GMT and five minutes later something that sounded like the barking of a dog.
Ms Roberts had suffered an injury to her eye, her head had been struck forcefully and she may have lost consciousness or part consciousness, the court heard.
DNA had been recovered from her black t-shirt, her handbag and a knot in her scarf.
Ms Evans said there was no microscopic evidence of a sexual assault.
According to a pathologist, she was alive when she entered the water and died from drowning.
"He can't say whether she was conscious, semi-conscious or unconscious when immersed in the water," she added.
Drowning and ligature strangulation were the cause of death, she said.
On Thursday the judge, Mr Justice Lloyd-Jones, will accompany the jury to the scene at Porthmadog.