Christina Edkins stabbing: Phillip Simelane admits manslaughter of Birmingham schoolgirl on bus Phillip Simelane has pleaded guilty to the manslaughter of Christina Edkins Sentenced to be detained indefinitely under the Mental Health Act 23-year-old stabbed Christina through the heart as she sat down on a bus Simelane then walked calmly off the bus and was arrested 100 yards away Criminal released from jail unsupervised despite concerns over mental health Had convictions for violent crime including threatening his mother with knife Christina's family say authorities could have prevented her brutal killing A knife-obsessed psychiatric patient will be detained for life in a mental hospital after he admitted stabbing a teenager to death as she took the bus to school to take a GCSE mock exam. Phillip Simelane, 23, today pleaded guilty to the manslaughter of Christina Edkins, 16, having plunged a blade into her heart in a motiveless killing during the Birmingham rush hour. The killer, who had a string of violent crime convictions including threatening his own mother with a knife, calmly walked off the double decker after fatally stabbing the teenager as she sat down. Today it emerged he had been jailed three times last year but despite the authorities having concerns about his mental health he was released at Christmas without any supervision. Christina's bereft family have said that had Simelane been monitored the killing of the 'bright and beautiful' 16-year-old would 'never have happened'. Brutal: Christina Edkins, 16, was stabbed to death by Phillip Simelane, 23, who has today pleaded guilty to her manslaughter Sentencing: Justice Thirlwall told Phillip Simelane he would be detained indefinitely under the Mental Health Act Chilling: Phillip Simelane calmly walked off the bus after killing the teenager, and was later caught 100 yards away after returning to the scene Justice: The parents of Christina Edkins, Jason and Kathleen (left and right), with her sister Joanne (centre) leave Birmingham Crown Court The killer, who this morning admitted the crime on the grounds of diminished responsibility, strolled off the bus and was arrested 100 yards from the crime scene after returning hours later on Thursday, March 7. April 22, 2007: Found in possession of a lock knife, aged 16, and handed a police reprimand. May 8, 2007: Discovered in an enclosed premises. No further action taken by police. March 5, 2009: Battery conviction for assault after pushing a young relative up against a wall. May 10, 2012: Criminal damage. May 11, 2012: Criminal damage. Received a six-month conditional discharge. May 21, 2012: Convicted and jailed for 11 days for assaulting a police officer who had responded to knife threats and assault against his own mother. June 1, 2012: Released from prison and spent 42 days out of custody. July 13, 2012: Convicted of assaulting and battery in the attack against his mother (which happened in May). Jailed for 101 days. October 15, 2012: Released from prison and spent seven days out of custody. October 22, 2012: Convicted of trying to steal a car, possession of cocaine and breach of licence of previous sentence for attacking mother. Spent 59 days at HMP Birmingham. December 13, 2012: Released unconditionally, without any supervision from Birmingham Prison. Lived rough for the next three months. March 7, 2013: Simelane fatally stabs Christina Edkins on the No 9 bus. Miss Edkins had been on her way to sit a GCSE mock exam when she was murdered on the number 9 bus which she caught on the Hagley Road in the city at 7.37am. Passing a hospital order on Simelane, Mrs Justice Thirlwall said anyone hearing the facts of the case would be 'disturbed' that he was living in the community with an illness of such severity. The judge told Simelane: 'At the time you attacked Christina you were suffering from a serious mental illness. Your mental function was wholly abnormal as a result of your mental illness. That is why you killed Christina - in your deluded state you thought she was a danger to you. It is difficult to understand how it came about that in December 2012 someone with your level of illness should have been sleeping rough with no one to look after you. The judge said: 'On at least two occasions an experienced specialist registrar in psychiatry insisted you needed in-patient treatment. It was not made available to you. The judge, addressing an impassive Simelane, said: 'You saw Christina get on the bus and CCTV shows in chilling detail you were watching her. After a few minutes you walked towards her and stabbed her. The blow of the knife penetrated deep in her chest - it took seconds. Christina had no chance. Referring to an incident a year before the fatal stabbing in which Simelane made death threats towards two girls on a bus, the judge went on: Those who gave statements - ordinary lay people - were of the view that you were mentally ill. The terrible reality is that Christina was the person who happened to be on the bus on the day you were overwhelmed by your illness. Several members of Christina's family were in court as Simelane, wearing a grey suit, white shirt and blue tie, entered his guilty plea. Cruel: Deranged Philip Simelane did not react as he was sentenced for plunging a kitchen knife into the chest of Christina Edkins on March 7 Stabbing: The scene on Hagley Road, Birmingham where a schoolgirl Christina Edkins was stabbed to death on a bus during the morning rush hour Giving the facts of the case, prosecutor Peter Grieves-Smith said: 'On March 7, Christina Edkins boarded a bus to go to school and she went to the upper deck and sat in a seat. Also on the upper deck was the defendant. Simelane boarded the bus at 5am, and had been reported by another passenger for sleeping on the back seat. When challenged by the driver, he produced a valid travel pass although it was later revealed this did not belong to him. Mr Grieves-Smith said: 'He was carrying a white plastic bag and the CCTV shows his top bearing a distinctive animal print logo. In his bag is what the prosecution say was a knife, 10 to 12 inches in length. Christina Edkins boarded just after 7.30am and went upstairs and sat on her own. Within seconds the defendant got up and moved forwards three seats and pulled out the knife, which he then hid. Questionable: Mental patient Simelane was held by officers within hours of the stabbing, but there are questions about whether he should have been free at all Tragic: Christina Edkins, 16, was in her school uniform on the top deck of the bus in Birmingham city centre when she was stabbed in the chest by Phillip Simelane, 23 Simelane then got up and walked forward towards where Christina was sitting, 'leant closer to her', stabbed her and started to walk off, the court heard. 'Such was the nature of the attack, nobody else on the upper deck realised what had happened until Christina reacted,' Mr Grieves-Smith said. Other passengers on the bus tried to treat and comfort Christina after a witness heard her struggle for breath and say she had been stabbed. Paramedics who arrived at the scene at 7.37am found the schoolgirl was not breathing and had no pulse and she was pronounced dead shortly before 8am. Doctors were also diverted to try to help Christina, Mr Grieves-Smith said, telling the court: Everybody who could attend did, and everybody who did attend did all they could to assist but sadly without any success. Simelane was arrested around four and a half hours after the stabbing in a nearby street. A police search of the area led to the recovery of a white bag containing the weapon used to stab Christina, a mobile phone, a smoked spliff, and a piece of paper bearing Simelane's fingerprints. Simelane was detained under the Mental Health Act and admitted to a psychiatric hospital. Paranoid schizophrenic Phillip Simelane had a history of mental illness, dating back to when he was just 14. In shock: The killing in Birmingham brought the city to a standstill as the bus (centre) was combed by forensic officers in March Upsetting: Christina's family were in court to hear her killer plead guilty but believe he should never have been able to commit the crime West Midlands Police have admitted he was the subject of a number of warning 'markers' on the police national computer about weapons, violence, self-harm and suicide. Detective Sergeant Harry May, senior investigating officer, said: 'Because he was released from serving for minor offences, he was released unconditionally and there was no supervision and probation involvement.' It has also emerged he had threatened his own mother last May with a knife, just months before he stabbed Christina. The 23-year-old was born in Swaziland, Southern Africa, and arrived in the UK at the age of nine and lived in Walsall with his siblings and mother, who had separated from his father. Simelane began suffering mental health issues as a schoolboy and was known to mental health professionals in the West Midlands and the probation authorities - having served three prison sentences in 2012. Before the brutal killing of Christina he spent two spells inside Hewell, near Redditch, and at Birmingham Prison in Winson Green. He had been released from custody three months before the killing but was under no supervision or reporting orders. The criminal history of the diagnosed paranoid schizophrenic includes a violent attack and knife threat against his own mother at the family home, for which he was jailed last July. Despite being caught with a knife at the age of 16, the attack would prove to be the most serious warning about his violent tendencies. As well as assaulting her, he had also held a knife to her stomach - and then punched a police officer in the face who had responded to the emergency call. Simelane's mother had called in police 21 times since he was 14 after a string of violent confrontations at the family home. In one incident, back in 2009, he was convicted of assaulting a young relative who had been held up against a wall. In the three months before the attack on Christina, the killer's terrified mother even refused one-on-one contact with her son, who had been released from prison to no fixed address. Investigation: The scene on the Hagley Road, Birmingham, where bus passenger Christina Edkins died after being stabbed Evidence: When police caught him Simelane had a plastic bag which contained the 12ins knife used to kill Christina She was so scared Simelane, that she would throw belongings and money down to him from an upstairs window when he turned up at the home to demand them. She had also tried countless times to convince her son to engage with health care professionals and tried to get support for him. Police say Simelane, first started suffering from mental illness as a young teenager and rarely went to Edgbaston's George Dixon School between the ages of 14 and 16, where his mother claimed he was a victim of bullying. She also tried to convince her son, who rarely came out of his bedroom, to seek help, but without success. Police say his diagnosis as a paranoid schizophrenic was only made after his arrest for Christina's killing, by psychiatrists working for both the prosecution and defence. Simelane left school with no qualifications and had enrolled on a course at Bournville College before the attack, but had never attended. Speaking about the effect the case has had on Simelane's mother, Detective Sergeant Harry May, said: 'She is obviously devastated about what has happened and has the utmost sympathy for the Edkins family.' Life taken: Christina Edkins died from a single stab wound to the heart in an apparently motiveless attack seconds after sitting down on a double-decker bus in Birmingham, 800 people turned out for her funeral Bereft: Kathleen and Jason Edkins, parents of Christina Edkins outside Birmingham Cathedral in March Christina's pure white coffin was adorned with purple and white flowers which arrived at the cathedral by horse-drawn carriage In March 800 mourners - wearing purple which was the teenager's favourite colour - packed Birmingham Cathedral to say farewell to her. Her devastated parents Jason and Kathleen Edkins wrote on a card next to her coffin: "Our beautiful princess Christina, we will always miss you and you will live in our hearts forever, mummy and daddy xxx. The couple, who encouraged Christina to attend a school out of Birmingham so she could get a better education and pursue her dream of being a nurse, also wrote a poem to their daughter which was read out. It read: "We love u (sic) more than anything, more than words can say, you meant the world to us, bringing happiness every day. A daughter and sister, always in our heart, you will stay with us forever, even though we have to part. A beautiful teenager, a princess through and through, even if u (sic) are not here, our thoughts will always be of you. Bereft family pay tribute to 'bright, beautiful and caring' Christina The family of the 'beautiful, bright, caring girl' whose life Phillip Simelane took away with one single violent act have described their struggle to come to terms with the loss. Christina Edkins' parents and siblings said the senselessness of the crime had made their grief that much harder to bear on top of the loss of the schoolgirl, just two weeks after her 16th birthday. Jason and Kathleen Edkins, and Christina's brother Ryan and sister Joanne, also made it clear that questions remain over why Simelane had not been supervised after his release from jail at the end of 2012. Arrival: Family members of Christina Edkins, mother Kathleen (right), sister Joanne (centre) and father Jason (far left) arrive at Birmingham Crown Court today Her great uncle Chris Melia added that if 23-year-old Simelane had been properly monitored after his release, the attack on the top deck of the No 9 bus on the morning of March 7, 'wouldn't have happened'. The teenager's family thanked all those whose 'many acts of kindness' have made their trauma a little easier to bear, including good wishes from people who never knew the schoolgirl but who had been touched by her loss. Verdict: Chris Melia, Christina Edkin's great uncle, says had Simelane been watched properly she would never have been stabbed to death Christina, they said, came from 'an ordinary, quiet and hard-working family' and was 'loved by everyone'. It was her caring nature that lent a desire to become a nurse or a midwife, Mr and Mrs Edkins said. They also revealed the pride in finding out she had passed 11 GCSEs, tempered with the bittersweet knowledge she was not there to open her own results letter, nor wear the lilac dress she bought for the school prom. Students and teachers at Leasowes High School in Halesowen, West Midlands, paid their own tribute to Christina, dedicating the prom to her memory and writing their own personal messages in the school's yearbook which her mother and father found 'deeply moving'. In a statement, her family said they had been pulled apart by the 'horror, distress and pain' of Simelane's devastating crime, and had been robbed of their privacy by the high profile of the case. 'Nothing will restore Christina to us,' they said. The loss of a child is the worst thing that can happen, made even more grievous by such a senseless crime. The family are all innocent victims and must pay the penalty as we stand helplessly by and watch the lives of the people we love shattered like glass, knowing we can never put the fragile pieces back together. Welcoming the outcome of the court hearing, the family said it would 'bring an element of resolution in that the sentence passed means the public is protected from this man'. They added: 'However, he was allowed the freedom not only to take the life of an innocent child but, in doing so, to ensure the lives of the people whom she loved are forever affected as a result of his crime.' Despite the family's loss, Mr Melia said there was 'no feeling of vengeance or retribution' toward Simelane. 'It's just a matter of 'get him out of society',' he added.