A mother who found her teenage son tortured and beaten to death in their home had to barricade herself in a room with his body when his killer tried to attack her.

After killing Michael Jones, 18, the murderer may have waited for several hours for the victim’s mother, Kathleen Kirby-Jones, to return from work so as to kill her too, police believe.

When she got home at 5.15pm a week ago she went to put back some chairs that had been disturbed in their computer room and saw her son lying behind the door with horrific head and neck injuries. He had been attacked with a machete-type weapon.

As she went to him she heard someone running towards the room. Ms Kirby-Jones, 44, barricaded the door as the killer tried to enter.

Detective Chief Inspector John Macdonald, who is leading the investigation, said that the killer may have targeted both mother and son. He said: “We are now aware that the suspect had remained in the property for some time and was still in the flat when Michael’s mother arrived home.

“She was on the telephone to a relative when she saw the body of her son and screamed out. As she did so she heard someone running down the stairs and they tried to get into the room. She pushed back to keep it closed and then barricaded herself in. There was a pushing match and she managed to keep the suspect out. We cannot imagine a worse scenario for a mother to have to find her son murdered and then try to defend herself.”

Ms Kirby-Jones, a personal assistant, called police and they had to break into the first-floor flat in Edmon-ton, North London, because she would not leave the safety of the room.

Police are baffled by the “vicious and horrendous” murder. Mr Jones was a hard-working teenager who had never been in any trouble. He was a geography student at Queen Mary’s University in East London. Ms Kirby-Jones paid tribute to her son yesterday. “He was always making jokes, always so helpful, so considerate and loving. He loved his books, he really enjoyed his university work, he was fashion conscious, loved clothes and was even a little vain.”

His father, also called Michael, “ added: “He was a role model to his nephews, cousins and younger kids. Every kid he knew looked up to him.”

A postmortem examination gave cause of death as severe head injuries and a stab wound to the chest.

Officers are appealing for help in finding some jewellery taken from Mr Jones. An 18-20in, 9 carat gold neck chain with a crucifix and a distinctive gold ring with the initials MJ and three white stones on the M initial are missing as well as a pair of glasses from Specsavers. They also want to trace a blue 3 Series BMW, registration number N118 FLA.

Police have been given a further 36 hours to question a 45-year-old man arrested in connection with the killing.

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