Luke Mitchell lied to police about his affair with a lookalike of murdered 14-year-old Jodi Jones, appeal judges heard.

He did not want officers to know he had spent three hours on the phone to Kimberley Thomson in Kenmore, Perthshire, immediately after an evening of sex with Jodi, said advocate depute John Beckett QC, for the Crown.

Although it might be speculation, Kimberley could have been the reason for a fight with Jodi, Mr Beckett told the judges at the Court of Criminal Appeal in Edinburgh.

Mitchell, 19, is trying to overturn his conviction for the killing in Dalkeith, West Lothian, in June 2003.

The jury at his trial in 2004 heard Mitchell was planning to visit Kenmore during the school summer holidays, days after Jodi's death in June 2003.

The trial also heard neither girl seemed to know about the other.

Mr Beckett told the appeal judges: "It offers a possible explanation for conflict with Jodi at the time.

"If he was going to disappear to Kenmore to visit a girl Jodi didn't know anything about, the potential for conflict was there."

The judges were informed Mitchell told police investigating the murder he had not spoken to Kimberley since January 2003, but records showed 79 calls between then and the end of June.

There was also a Valentine's Day visit.

Just two days before her murder, Jodi left Mitchell's house, by taxi, about 10pm. After that there was a series of long telephone calls, totalling more than three hours.

Mr Beckett said it was an example of how Mitchell was prepared to lie, even in the face of known evidence.

Earlier, the court heard the fact Mitchell led members of Jodi's family to where her body was found was "a cornerstone" of the case against him.

The QC said his story about finding Jodi was contradicted by the girl's gran, Alice Walker, Jodi's sister, Janine, and Janine's fiance, Steven Kelly.

Mr Beckett also claimed Mitchell had later lied six times when questioned by police about the find.

The hearing continues.