The Jodi Jones trial has restarted at the High Court in Edinburgh.
A new jury was chosen at the High Court in Edinburgh
Luke Mitchell, 16, denies murdering the 14-year-old in Dalkeith, Midlothian, in June last year. He has lodged special defences of alibi and incrimination.
A jury of eight women and seven men began sitting in the trial, which is expected to last until the new year.
The judge asked them to consider very carefully if they could try the case.
The original jury was discharged on Tuesday after two days of evidence.
The court began the process of selecting the new jury on Thursday morning.
The judge, Lord Nimmo Smith, asked about 100 prospective jurors to make sure they would be able to serve free from prejudice.
He told them: "It causes major problems if jurors have to be excused after the start of a major trial, as we have already seen this week."
The jury were later shown video footage and photographs of the Roan's Dyke path next to woodland where the schoolgirl's body was found last summer.
They saw pictures of letters carved into a tree, which matched the initials of Mr Mitchell and the dead girl.
The letters LM and JJ were cut into bark near the scene of the alleged murder.
Detective Constable Rory Hamilton showed photos and a video taken by police to the court.
On seeing a close-up of two small trees, prosecuting advocate depute Alan Turnbull QC asked:. "Do we see that on the upper part of the right hand tree, as we look at it, there appear to be some initials?"
"There are, yes," the detective said.
"They appear to be, on top, the letters LM and below the letters JJ. Do they appear to have been formed by cutting away the bark?" asked Mr Turnbull.
High stone wall
"They do, yes," said Mr Hamilton.
The jury members were shown a video of the route along the Roan's Dyke path from the Easthouses end to a gap in a high stone wall. The journey took six minutes and 44 seconds.
They were also shown a CCTV security camera picture of Allen Ovens, described as the partner of Jodi's mother, taken at a Tesco garage in Bonnyrigg on the day Jodi died.
A police reconstruction of his drive from the garage to his Easthouses home took seven minutes and 30 seconds.
It has been alleged that Mr Mitchell, who was 14 at the time, attacked Jodi, of Parkhead Place, Easthouses, Dalkeith, on 30 June, 2003, hitting her about the head and body and compressing her neck, restricting her breathing and causing her to fall to the ground.
The charge alleges that Jodi was repeatedly struck with a knife both before and after she died, inflicting wounds to her face, ear, mouth, breast and abdomen. It has also been alleged that a ligature was applied round her arms.
Mr Mitchell has lodged papers in court blaming person or persons unknown for Jodi's murder.
He claims that around the time she is thought to have met her death he was in or near his home in Newbattle Abbey Crescent, Dalkeith.
He has also denied charges of possessing a knife or knives and being concerned in the supply of cannabis resin to Jodi and to other school pupils.
The trial continues.