A controlling boyfriend shouted about demons and the occult as he brutally stabbed his girlfriend to death, a court heard.
Ivan Griffin, 24, plunged a kitchen knife through Sabrina Mullings' heart and liver while her daughter Hayleigh slept in their flat in Upper Norwood, south London.
Hayleigh, 22, and her boyfriend Chaise Gore were woken up when Griffin started shouting about 'releasing demons' and 'drinking blood' at 5.30am on March 13, jurors heard.
When they rushed out of their bedroom and tried to get into the room, Griffin struggled to keep them out as Ms Mullings's blood seeped out from under the door, it is claimed.
They eventually barged through the door and found the 38-year-old victim's naked body laid out on a dressing gown on the floor of the blood-soaked scene.
The Old Bailey heard Griffin told the couple he had stabbed Ms Mullings 'because he loved her' before he fled the scene. He was arrested in Camberwell later that day and charged with Ms Mullings's murder.
Prosecutor Timothy Cray, QC, said when Hayleigh and Mr Gore were woken up, the noise 'was bad enough that they got out of bed and went across the corridor'.
'It's now certain that what they were becoming witnesses to was a scene of fear and extreme violence, and in the next 15 minutes or so what they heard, what they saw, must have seemed to them as unreal,' he said.
'Most of the noise in terms of the shouting was coming from the defendant and his words were strange, things like they had not heard from him before. Talk along the lines of releasing demons, drinking blood, strange talk of that kind.'
As Griffin struggled to stop Hayleigh and Mr Gore from getting through the door into the kitchen, Mr Cray said 'they started to see blood seep out from under the door'.
When they broke through the door and got into the front room and kitchen they were 'covered in blood'.
Jurors heard Ms Mullings still had a faint pulse but must have been 'minutes or seconds from death'.
Mr Cray said before Griffin fled the scene he told Hayleigh 'that he had stabbed Sabrina because he loved her and he had even wanted to stab himself in order, in his words, to join their blood together'.
Griffin had wounds on his chest but they were not deep, the court was told.
Ms Mullings was pronounced dead at the scene and a post-mortem revealed she had suffered two stab wounds inflicted with 'severe force'.
One fractured her ribcage and punctured her heart, while the other plunged through her abdomen and into her liver. After Griffin was arrested he admitted stabbing Ms Mullings - but he claims he is not guilty of murder by way of diminished responsibility relating to mental illness.
Jurors were told they will see evidence about Griffin's mental state at the time and around the time of the killing.
Two psychiatrists have assessed the defendant, but Mr Cray said 'there's no evidence that this defendant suffered from any mental illness before the attack'. Mr Gore had described the murder suspect as a 'normal sort of guy', though Hayleigh claims he was a controlling boyfriend who had shown a temper.
Mr Cray said: 'Either the defendant was suffering from some previously undiagnosed mental illness not picked up before which seems to have left him soon afterwards, or the real explanation for this killing is something much more normal, that this is a case of domestic violence.'
The prosecutor said Griffin has tried to 'disguise what he's done in the language of mental illness' because 'he can't or doesn't want to face up to it himself'.
Griffin, of Ravensdale Gardens, Upper Norwood, south London, denies murder.
He had lived in the flat next to Ms Mullings's home when they first met.
The trial continues.