Mitchell was convicted after Scotland's longest single-accused murder trial
Convicted killer Luke Mitchell is seeking to have his sentence cut at an appeal court hearing next month.
Mitchell, now 20, was ordered to be detained for life after being found guilty of murdering 14-year-old Jodi Jones in June 2003.
Lord Nimmo Smith said he should serve a minimum of 20 years in jail before he became eligible for parole.
Mitchell is set to challenge the ruling at a hearing at the Court of Criminal Appeal in Edinburgh on 16 December.
Mitchell was aged 14 when the mutilated body of his teenage victim was found in woodland near Dalkeith in Midlothian.
He denied the murder but was found guilty by a jury at the High Court in Edinburgh in 2005, when he was aged 16.
Mitchell continued to maintain his innocence, but in May of this year appeal court judges rejected a wide-ranging legal challenge against his conviction.
Lawyers acting for Mitchell are now seeking a reduction in the punishment part of his life sentence, the minimum term he must serve before he can apply for parole.