With reporting from Alison O' Riordan.

Warning: This content is of a very sensitive nature, readers may find the details of the report disturbing. The two boys convicted of the murder of 14-year-old Ana Kriegel have been sentenced at the Central Criminal Court. Boy A who violently sexually attacked and murdered schoolgirl Ana Kriegel at an abandoned house has received a life sentence that will be reviewed after 12 years. Passing sentence at the Central Criminal Court today, Mr Justice Paul McDermott said that Ana Kriegel's life was and is of "supreme importance" and her short life should not be defined by the crimes committed against her. "The two boys bear responsibility for her murder and must be accountable and accept the consequences of their crimes," noted the judge, adding that this was a murder of the "most serious, disturbing and shocking type" because of the extreme violence used. Boy B who lured "lonely and vulnerable" schoolgirl Anastasia Kriegel to an abandoned farmhouse, where she was violently sexually attacked and murdered by his friend, has been sentenced to 15 years detention with a review after eight years. Passing sentence at the Central Criminal Court today, Mr Justice Paul McDermott said that Boy B had watched as Ana was sexually and brutally assaulted and did not take steps to assist her, leaving the scene without seeking help. He was fully aware of what was done and was indifferent to her plight, said the judge. He had constructed lies about the incident in a "clear and brazen way", indicated the judge, and was "naive" to think these lies would not be discovered. Referring to Boy A, the judge emphasised that he was not satisfied that the teenager had told the whole truth as a good degree of what he said was "self-serving". The "mental terror and suffering" that he inflicted on Ana was of a very high degree, said the judge, adding that he had "devastated and caused huge sorrow and loss" to the victim's family. There is little appreciation of the enormity of what has been done, he said. Before delivering the sentence this morning, the judge said Ana's precious right to life "entitled her to live it to its full potential". Ana was a "lovely and loving child within a lovely family" and she will be remembered as a child, daughter and sister, he said. At his sentence hearing last week the court heard that Boy A, who now accepts that he caused Ana's death, had been the subject of psychiatric and psychological reports in which he described the his attack on her. This included "various actions including a headlock and choke hold, kicking, hitting her with a stick and ultimately a block which he either threw at her or hit off her head on three occasions." However, the teenager continued to deny sexually assaulting Ana and put forward "an alternative explanation" for the forensics found at the scene. At his sentence hearing last week, the court heard that Boy B does not accept the jury's verdict, which found him guilty of murdering the fourteen-year-old, and maintains the position that he had no part in what happened. Defence counsel Damien Colgan SC said reports handed into the court stated that his client was at a low risk of re-offending and had "personal difficulties" as well as "suicidal tendencies". The barrister further pointed to the boy's remorse and "guilt in respect of his inactivity and why he didn't intervene to assist Ana." In his closing speech, prosecution counsel Brendan Grehan SC told the jury that Boy B "lured" Ana to her death, saying: "Any suggestion that he assisted in this matter without the knowledge of what was to happen is not credible." It was the prosecution's case that the evidence against Boy B was largely gleaned from what he said in his garda interviews, where he told a mixture of "lies, untruths and half-truths". It was the prosecution's case that gardai had gathered "overwhelming" evidence against Boy A. It included CCTV footage contradicting his version of events, forensic evidence linking him to the scene and to Ana's body, phone internet searches for "abandoned places in Lucan" and circumstantial evidence including injuries he presented with on the evening of May 14, which he claimed were the result of a random assault by two men in the park. During the trial, it emerged that semen matching Boy A's DNA was found on Ana's top at the scene and his DNA was on her neck and on both ends of a long piece of insulating tape that was wrapped around her neck. Her blood was found on his boots and on a backpack, homemade 'zombie' mask, knee pads and gloves gardai found in a wardrobe in his bedroom. There was evidence that Ana had been sexually assaulted as her clothes were torn and strewn around the room of the derelict building where she was found. Her blood was visible on every wall and forensic scientist John Hoade said she was struck repeatedly on the head with a weapon while she lay on the floor and was then moved to another part of the room. The jury heard that the "lonely and vulnerable" schoolgirl went missing after leaving home on the evening of Monday May 14, 2018 and was found three days later in Glenwood House, which was about a 20 to 30 minutes walk from her home. She was naked but for a pair of socks and former State Pathologist Marie Cassidy found she died from blunt force injuries to the head and injuries to the neck.