A daughter stabbed a family friend to death after he tried to calm her down when she headbutted her mother during a drunken row, a court has heard.
Rebecca Press is accused of plunging a 7.5cm knife into the chest of Richard Marc Ash as he tried to diffuse tensions between her and her mother, Michelle Press, on July 17, last year.
The 31-year-old had turned violent with Mr Ash, who had been acting as a peacemaker, saying: 'Will you just calm down Bec, what is wrong with you?' before he died.
It is alleged the 57-year-old, who had called 999 as the row got more and more heated, ended up being stabbed close to the heart by Press, who later told her mum 'I have stabbed your f***ing best friend'.
Rebecca Press, pictured, is accused of murdering Richard Marc Ash by stabbing him in the chest
The 31-year-old, pictured, is alleged to have stabbed Mr Ash as he tried to calm her down during a drunken row
Cardiff Crown Court was told on Monday that the incident took place at a house in New Tredegar, Caerphilly, with Mr Ash paying the price for trying to help 'with his life'.
Prosecutor Jonathan Rees KC said Press had spent the day drinking in her mum's garden with Mr Ash and other neighbours.
But she flew into a rage hours later when she returned from the pub and headbutted her own mum during a family bust-up in New Tredegar, Gwent.
Mr Rees said: 'Rebecca Press had picked up a knife and stabbed Richard Marc Ash with it, just above his heart.
'Mr Ash, known as Marc, was unarmed. The full length of the blade - up to the handle - plunged into his chest, some 7.5cm or so, and pierced the aortic arch above his heart.
'Mr Ash rapidly lost blood from that injury to the aortic arch, leading to his cardiac arrest and death.'
The court heard Press had split with boyfriend Ashley Allen in the days leading up to the attack and had been invited to stay with her mum.
Mr Rees said Press had been 'becoming increasingly frustrated' as she sent a string of messages to her brother Gavin Press in a bid to find out Mr Allen's whereabouts.
The court heard Press suspected Mr Allen had been cheating on her - and she sparked a row when brother Gavin turned up to their mum's home at 12.30am on July 17.
Mr Rees said: 'She began screaming at her brother Gavin, asking him to tell her who his friend, Ashley Allen, had been 'shagging'.
'Michelle Press shouted at them both to be quiet or to leave.'
The court heard Press, who had taken Valium, thought her mum Michelle had spat at her during the family row - so she 'lunged forward' and smashed her teeth against her mother's nose.
Cardiff Crown Court heard mum Michelle escaped to her bedroom while Mr Ash shouted: 'Will you just calm down Bec, what is wrong with you?'.
The court heard Mr Ash dialled 999 but the call was cut off and police called him back just before 1am.
He told officers it was 'kicking off' at his neighbour's home because there were two people who were not wanted there.
Mum Michelle then called 999 at 1.07am to say her daughter had 'gone nuts and headbutted her' and asked the police to send someone quickly.
The court heard just moments later Press 'burst into the bedroom in a rage' and screamed at her mum: 'I have stabbed your f***ing best friend'.
Press, pictured, is alleged to have headbutted her mother moments before stabbing Mr Ash
Press denies murdering Mr Ash in New Tredegar, Caerphilly, on July 17, last year. Pictured: Cardiff Crown Court, where the trial is being held
Michelle then made another call just two minutes later to request an ambulance because 'someone had been stabbed.'
The court heard Press left a voicemail for her ex Mr Allen at 1.15am to say: 'Ash it's really bad. It's really f***ing bad. I've just stabbed someone and killed them.
'I've just murdered someone, please phone me now. F*** (screams). I've just murdered someone'.
The court heard Rebecca Press fled the scene to hide in nearby bushes before police arrived at the address just four minutes later.
Officers found her brother Gavin standing in the living room 'looking pale and in shock' while pointing at Mr Ash lying on the floor in the kitchen.
Mr Rees said: 'Inside the kitchen Marc Ash was lying on his right hand side in a recovery position, that Gavin had helped him into.
'His head was near the entrance to the kitchen and his feet pointing towards the wall with the window at the end of the room.
'Looking around the kitchen quickly, the officers saw that a drawer from one of the kitchen units had been pulled out and emptied on to the floor, with knives and forks everywhere.'
The court heard a Tesco branded KP/9 knife was found near to the fridge covered in Mr Ash's blood.
Emergency Response Doctor, Dr Matt O'Meara, arrived at the scene at 1.44am but Mr Ash's injuries were found to be 'unsurvivable' and he was pronounced dead at 2am.
The court heard Press attempted to hide from police while ringing her ex-partner's mum Stephanie Allen in a bid to get help escaping - but she refused.
Police spotted Press walking near to the address at 3.14am before she was arrested and feigned surprise saying: 'What has someone died?'
In a prepared statement to officers, she claimed she 'got involved' in a row between her mum and brother when Mr Ash stepped in.
She said: 'Marc has been very aggressive towards me and started pushing and grabbing me.
'He has then grabbed me by my arms, causing bruising to the inside of both arms, and started trying to push me and pin me against the kitchen.
'I was fearful as to what he was going to do because I've never seen him act like that before. Marc is normally a chilled and mellow character but wasn't at this point.
'In self-defence, I have tried to push him away but he has continued to be aggressive.
'I have picked up the closest item to me from the kitchen worktop, which was a knife and I have hit him with it.
'I didn't intend to stab him in the chest but accept this is what I did.
'I had no intention to kill Marc, I was acting in self-defence and used reasonable force in the circumstances.'
Press, of Trecenydd, Caerphilly, claimed she was acting in self defence. She denies murder and assault occasioning actual bodily harm.
The trial, before Judge Recorder Tracey Lloyd-Clarke, continues and is due to last three weeks.