Luke Mitchell has failed in his bid to overturn his conviction for the "truly evil" murder of his 14-year-old girlfriend Jodi Jones.

After the teenage killer was yesterday led away from court to continue his life sentence, Jodi's mother spoke of her relief that his appeal had failed.

Judith Jones covered her mouth with her hands as the judges announced their decision at the Appeal Court in Edinburgh. As she left court she said she felt "relief, total relief". Asked her reaction to the ruling, she said: "Brilliant."

Her comments were in stark contrast to those of Mitchell's mother, Corinne, who was also in court. She remained defiant. "Luke's innocent - the fight goes on," she insisted.

While the judges rejected claims of a miscarriage of justice, they also issued a damning criticism deploring the "outrageous" bullying tactics used by police during the questioning of Mitchell as a 15-year-old suspect.

Now 19, Mitchell was given a life sentence in 2005 after being found guilty of killing the schoolgirl, whose mutilated body was found near her home in Dalkeith, Midlothian, in June, 2003.

The trial judge, Lord Nimmo Smith, said at the time that it was one of the most appalling crimes ever encountered in Scotland and was a "truly evil" killing.

However, defence QC Donald Findlay lodged an appeal arguing that Mitchell was the victim of a miscarriage of justice in an unfair trial which relied purely on circumstantial evidence.

Yesterday, dressed in a dark suit with his long hair tied back in a ponytail, Mitchell sat silently in court as it was announced that his appeal had failed. The panel of three judges rejected all six grounds for quashing his conviction. His only reaction was a flicker of a smile towards his mother as he was led into court.

Announcing the ruling yesterday, Lord Hamilton, the Lord Justice General, flatly renounced the defence counsel's claim that anyone examining all the evidence together would feel "a sense of unease" about the conviction.

Lord Hamilton said: "We have already addressed and rejected the ground of appeal based on the proposition that no reasonable jury, having regard to the totality of the evidence, could have returned a guilty verdict. As to other matters of complaint, while there may be cases where the combined effect of a series of unsatisfactory features in a trial may result in a miscarriage of justice, we are not persuaded that this is such a case."

Referring to the questions and answers from a police interview with Mitchell which were elicited by the prosecution during the trial, despite defence claims that the questioning was "wholly and manifestly unfair", Lord Hamilton said the trial judge was right to allow this evidence to be admitted.

But he launched a stern rebuke of the way the police conducted the questioning. He said: "We are driven to the conclusion that some of the questions put by the interviewing officer can only be described as outrageous.

"At times the nature of the questioning was such that the questioner did not seem to be seriously interested in a response from the appellant but rather endeavouring to break him down into giving some hoped-for confession by his overbearing and hostile interrogation. Such conduct, particularly when the interviewee was a 15-year-old youth, can only be deplored."

Mitchell will be the subject of a separate forthcoming appeal against the length of his sentence of at least 20 years before applying for parole.