A forensics expert has told the April Jones murder trial of "strong evidence" that fragments of bone found in the home of the defendant Mark Bridger were human.
The expert has also told the court that one of the bones was likely to come from a child between the age of four and eight.
Dr Julie Roberts told the court she was asked to examine fragments found in the fireplace at Mr Bridger's cottage in Ceinws.
She told the court all of the fragments are burned human bone, in her opinion.
Dr Roberts said there is "very strong" evidence that three of five fragments are human skull, and "strong" evidence one fragment is human skull. The final fragment was not able to be confirmed.
One fragment, she said, was very characteristic of a human child's skull aged between four and eight.
A DNA test was performed on one fragment, but it was too badly burned, so no DNA could be obtained.
Dr Roberts told Mold Crown Court that the fragments found in Mark Bridger's home were compared to non-human bone fragments, from many animals, at the University of Liverpool.
She said the comparisons showed that the shape and thickness of the bone was different, and architecture of the bone entirely different.
Dr Roberts said it is her opinion that a small amount of bone was transferred to the fireplace - put in as fragments, rather than representing the remains of a body that had been burned there.
Asked by police as part of their investigation if the bone could be the result of a clean-up process at the cottage, Dr Roberts said yes.
One possible interpretation, she said, was small fragments of bone on a cleaning cloth which was then put into the fire - although that was not the only possible interpretation.
Cross-examined by defence barrister Brendan Kelly QC, Dr Roberts said the burned bone does not constitute the full skeleton of a child, or the entire skull of a child.
There were no fragments of lower jaw or facial bone or teeth or enamel.
In her opinion, she told the court, "if they were there you would find them... particularly teeth."
The defence called its first witness - forensic anthropologist Professor Susan Black.
She told the court she couldn't age the fragments recovered from the fireplace and sink traps, and couldn't confirm whether they are human or non-human
Prof Black told the court prosecution's experts had drawn an "unsafe conclusion" by stating the bones were fragments of human skull.
She said: "It's a very unsafe conclusion because I genuinely do not believe there is the evidence to support it."
She also added there was "no certainty" about which part of the body the bones originated or their age.
Cross examined by prosecutor Elwen Evans QC , Prof Black explained why she couldn't say the origin of the bones.
"They are too small, they are too damaged, there are no identifiable anatomical features," she said.
Mark Bridger denies murder, abduction and perverting the course of justice. The trial will continue on Wednesday.