AN AXE-WIELDING masked killer who murdered his ex-partner and her son was last night beginning a prison sentence of at least 30 years.

Michael Kelly donned a horror mask and lay in wait for former lover Sally Cox to return from walking her dog before bludgeoning her to death in her kitchen.

He went on to kill her 22-year-old son Martin Faulkner in his bedroom while his sister Amy Cox, 19, was left in a coma after jumping from a first-floor window to escape.

The murders took place early on December 13 last year at the family’s home in Mold Crescent, Banbury.

At Oxford Crown Court yesterday, 46-year-old Kelly admitted two charges of murder and one of grievous bodily harm with intent.

Benjamin Aina, prosecuting, said the defendant met 43-year-old Sally Cox in January last year through a dating website. The couple, who both worked for parcels firm DHL at its Banbury depot, moved to Mold Crescent the following month.

Kelly was “jealous of Miss Cox’s children and discouraged her friends from visiting” and would watch over her when she was on the computer, Mr Aina said.

In November, Miss Cox ended the relationship and Kelly went to live with his mother in Hatch Road, Stratton St Margaret, Swindon.

Towards the end of the month, he wrote abusive Facebook posts about Miss Cox and texted her “I’ve got one more surprise for you”.

Mr Aina said: “Sally felt threatened and scared of Mr Kelly. She thought he was continuously watching her. She slept with a knife under her pillow.”

On December 8, after buying the axe from a Wickes DIY store in Swindon, Kelly told a friend on Facebook “a part of me wants to see her suffer so much... am I screwed up inside? I think I really must be”.

Miss Cox suffered 14 wounds to her head before the defendant went upstairs attacked then tortured Mr Faulkner for up to 10 minutes before killing him, the court heard.

Amy Cox, who had gone into Mr Faulkner’s room to wake him after hearing her mother’s screams, jumped from a window to escape.

She ran to a neighbour’s house before slipping into a coma after hitting her head in the fall. She needed surgery for a blood clot on her brain.

Nick Rhodes, defending, said father-of-two Kelly had no previous convictions and had been married for 20 years. He said: “He wants this court to know he is not some monster, even though the offence itself is ghastly to contemplate.”

Mr Justice Saunders jailed Kelly for life, and said he must serve a minimum of 30 years before he can be considered for parole.

Krista Capell, who lives opposite the house, said: “I didn’t know anyone had died at that time but I said (to the police) it’s a domestic (argument) gone wrong. I saw one girl go off in an ambulance and I really felt for her.”

Miss Capell lives in a house where another murder took place in 2008. Mohammed Rashid was jailed for life for killing his wife Sughra Rani.