A man who claimed to have vital evidence which could clear Luke Mitchell of the horrific murder of his girlfriend, Jodi Jones, hoped to get a massive pay-off from selling his story, appeal judges heard yesterday.

Mitchell's defence team wants the Court of Criminal Appeal in Edinburgh to hear more about claims that a cannabis smoker with unusual tastes in rock music and internet violence might be a possible "suspect".

He was supposed to have been near the woods where Jodi, 14, was murdered in June, 2003, to have been acting strangely in the days following and to have sustained unexplained injuries to his face.

Donald Findlay, QC, said that the drug addict, named only as Mark Kane, "ticked all the same boxes" as Mitchell.

The lawyer told appeal judges that Mitchell's defence team had been made aware of the addict by another man, Scott Forbes, who had first come forward some 18 months after Mitchell had been convicted of Jodi's murder and given a life sentence.

Mr Findlay said that Mr Forbes had sworn out a statement last month and his claims were being investigated.

But John Beckett, QC, for the Crown, revealed that police investigations cast doubt on what Mr Forbes had told solicitors - and a BBC Frontline Scotland programme in May last year.

Mr Forbes had alleged that Mr Kane, a student at Newbattle Abbey College at the time of Jodi's murder, had written an essay on "killing a girl in the woods". He claimed that a teacher could confirm this.

Mr Beckett said: "The Crown had police take a statement from the lecturer which confirmed Kane wrote no such essay at all."

Mr Beckett said that Mr Forbes had told Mr Kane to co-operate "and we will get £50,000 from the newspapers".

In December, the appeal judges were told there was circumstantial evidence pointing to two possible "suspects". One was Mr Kane and the other was a local man in his 20s, James Falconer.

Mr Findlay told judges that he was dropping any further claims about Mr Falconer, who protested his innocence.

Mr Findlay wants the appeal judges to consider the argument that Luke Mitchell did not get a fair trial.

If they do not quash the conviction, he wants them to fix another date, to hear the new claims about Mr Kane.

Mitchell, 19, is trying to overturn his conviction for the murder of his girlfriend Jodi in June 2003.

The teenager's defence team say police acted unfairly, the trial should not have been held in Edinburgh because public feelings were running so high and that the prosecution used irrelevant "evidence" to blacken Mitchell's character and turn jurors against him.

Advocate depute John Beckett, QC, for the Crown, promised to give the court 20 reasons why the jury could return a guilty verdict, and asked the appeal judges to throw out the claims made by defence Mr Findlay.

"The Crown support the conviction and in my submission none of the grounds of appeal has been made out individually and there has been no miscarriage of justice," he said.

Mr Beckett continued: "I contend there is both sufficient evidence and a rational basis for the conviction."

Mr Beckett went on to argue that the jury believed key witness Andrina Bryson who said she saw Mitchell and a girl who could have been Jodi near the time of the murder. To do so they rejected Mitchell's alibi, claiming he was at home.

The hearing before Lord Hamilton - sitting with Lords Osborne and Kingarth - continues.