A sex offender has been jailed for fatally stabbing a forensic science student who dreamed of becoming a policewoman after befriending her on a canal towpath. David Marshall must serve a minimum of 20 years behind bars for the murder of Eni Mevish, a 20-year-old student at Staffordshire University. The 68-year-old stabbed her in the heart, lungs and liver six months after they met because he was 'jealous' of her other friendships, Stafford Crown Court heard. The pensioner had already served a jail sentence for assaulting a 14-year-old girl when he stormed her house Stoke-on-Trent in November last year to butcher her with a kitchen knife. Eni Mevish was killed by a sex offender who stabbed her in the lungs, liver and heart six months after she befriended him while out jogging . The pair are thought to have met around six months earlier when Miss Mevish, originally from Manchester, was out jogging. Prosecutors told the court Miss Mevish had received financial support from the pensioner, though the nature of their friendship is not clear. On November 9 the 20-year-old received a number of text messages thought to have been from Marshall. While she was watching a film with fellow student Rizwan Bukhari, Marshall is understood to have arrived at her house drunk. He asked Mr Bukhari to leave them alone before being heard 'swearing, shouting' and asking 'why didn't you text me?' The 22-year-old student then heard a 'slow scream' and tried to intervene but was struck by the sex offender's knife. David Marshall was on licence for sexually assaulting a 14-year-old girl when he killed Eni, a 20-year-old student . After Marshall had fled the scene he discovered Miss Mevish's body in a pool of blood and phoned an ambulance. She had been stabbed in her heart, liver and lungs and died in hospital. Appearing via video link in Stafford Crown Court Marshall was told he must serve a minimum term of 20 years and six months for her killing. Sentencing, Judge John Wait said it was clear the sex offender had intended to hurt her. 'You came to be jealous of her friendships with fellow students and sought to distance her from them. 'It is clear you had in mind violence when you went to her home.' The court heard how at the time of the attack Marshall was on licence for sexually assaulting a 14-year-old girl. 'At the time of this terrible offence you were on licence following a sentence for an offence of indecent assault,' added Judge Wait. 'It was a condition of your licence that you notify your supervising (probation) officer of any developing friendship with a woman. 'It is noteworthy that you failed to tell your supervising officer of the relationship (with Eni) though you were asked on many occasions.' In a statement released by police Miss Mevish was described as 'beautiful, clever and with her whole life ahead of her.' 'Eni was a loving sister and daughter who was taken from us suddenly and violently. 'We are so proud of her achievements. We are devastated by her death. 'Nothing can make up for that but we are glad Marshall is now paying for his actions.' The 20-year-old was studying to become a police woman at the time of her death. 'She would train really hard as she was so determined to join the police. 'Eni would run through the park and when she saw an officer she would say "that’s what I want to be’"- she just wanted to help,' said close friend Melanie-Vanessa Enyong. The 20-year-old aspiring policewoman was in her second year of a degree in Policing and Criminal Investigation when she was murdered . 'She only ever wanted the best for people because she loved exercising so much she used to encourage us to get out there with her - that was the type of person she was.' She is thought to have met Marshall while out running though details of their friendship are not known. One of her former lecturers said she was a 'warm-hearted and conscientious' student. Speaking on behalf of Staffordshire University, Professor Andrew Jackson said: 'She is greatly missed by all who knew her. 'Today’s events bring that loss into sharp focus and our thoughts are particularly with her family at this very difficult time.' She is thought to have met Marshall while out running though details of their friendship are not known. In the days after her death Thomas Barnes described how her housemate, Rizwan Bucari, had come into a shop to ask for help after seeing Marshall flee her body. 'She had blood pouring from a stab wound in her stomach, and cuts all up her arm. 'By the time the ambulance arrived, her breathing was very weak. I told them what had happened and moved so I didn't get in their way. 'It was surreal, after being in direct contact with that kind of situation it’s hard to concentrate on anything else.' Marshall stormed the student's shared house in Shelton, Stoke on Trent, (street pictured above) and killed her with a kitchen knife .
Eni Mevish, 20, was stabbed to death by David Marshall, 68, last November.
The pair had become friends six months earlier while Eni was out jogging.
He stabbed her at her home in the lungs, liver and heart with kitchen knife.
Marshall, who previously abused a 14-year-old girl, admitted murder.
He must spend at least 20 years behind bars before applying for parole.