Two teenagers blaming each other for the “frenzied” murder of Brianna Ghey in a Warrington park were “in it together”, jurors have been told before starting their deliberations. The 16-year-old was stabbed 28 times in her head, neck, chest and back in Linear Park, Culcheth, a village near Warrington, Cheshire, on the afternoon of 11 February this year. Two teenagers, identified only as girl X and boy Y, have been on trial for her murder for over three weeks and each blames the other for the murder. A jury at Manchester crown court was warned on Tuesday not to be tempted to “try to find an explanation” for the killing. In her closing speech, the prosecuting KC Deanna Heer told jurors: “You may find it hard to fathom how two children could behave the way they did. The temptation might be to try and find an explanation for what they did and why. They are only children after all. “But in a criminal case the prosecution doesn’t have to prove why a crime is committed, only that it has been. In murder cases in particular we sometimes never know why a crime is committed … Don’t be tempted to try and work out why they would do what they did.” She told the jury they did not have to decide who actually stabbed Brianna in order to find both children guilty of murder. Heer said they “may well conclude” that the boy inflicted at least some of the stab wounds using a hunting knife he bought for £13.50 on a skiing holiday six weeks before the killing. Brianna’s blood was found on his coat and shoes, as well as on the knife, the court has heard. Meanwhile, girl X’s barrister, Richard Pratt KC, told the jury: “There’s not even so much as a microscopically observable droplet of blood on girl X’s jacket or her shoes. There’s not a cell of girl X’s DNA on anything incriminating in this case.” But Heer reminded the jury that a forensic scientist, Jane Roughley, had told the court it was “entirely possible that Girl X had stabbed Brianna at least once, either before her blood started to flow or after it had started to flow”. The prosecutor also suggested that girl X may have used Y as her “hitman”, reminding them that she had once referred to her co-accused as a “Tesco John Wick”, a budget version of the assassin played by Keanu Reeves in the Hollywood film franchise. “You may think that’s why she referred to Y in that way, because he was her hitman,” Heer said. Heer told the jury that the teenagers were the only suspects, adding: “The evidence suggests that they both participated in Brianna’s murder in the following ways: firstly, they both encouraged the other to kill Brianna. Secondly they both contributed to a plan to kill Brianna. Thirdly, they both played a part in carrying out the plan. And fourthly, after they had killed her they both took steps to conceal and cover up their guilt.” She added: “The evidence suggests from first to last these two defendants were in it together.” The trial continues.