....with her knickers before laying her body in a 'crucifix' position when 'voices told him she was Satan' is given an indefinite hospital order
Gyekye, who is HIV positive, asked police about God and cannibalism after his arrest then bit one officer on the forearm, Judge Paul Sloan told Newcastle Crown Court yesterday.
Fortunately, the bite did not break the officer's skin and the disease was not transmitted.
He was apprehended after being found on the porch of an adjoining property on the morning of the killing and was initially arrested on suspicion of attempted burglary.
After officers made enquiries they discovered the lifeless body of his girlfriend and he was charged with murder. However, this was dropped after Gyekye pleaded guilty to the lesser charge of manslaughter with diminished responsibility.
Judge Sloan sentenced Gyekye, a French national who has suffered numerous psychotic episodes in the past, to an indefinite hospital order.
Gyekye had first suffered a psychotic episode in Paris in 2013 when he threatened violence towards strangers in the French capital.
He was taken to hospital and given anti-psychotic medication, but he did not continue to take this while living in the UK, Mr Recorder Sloan told the court.
Gyekye told a specialist after Sarrah's killing that voices in his head told him his girlfriend was Satan and he had to kill her if he wanted the real Sarrah back.
Judge Sloan said: '[You told the specialist] when you looked at her she had the face of a demon.'
There were at least 12 blows to Sarrah's face, as well as wounds created by a round-edged weapon.
Judge Sloan said: 'You arranged her body so her arms were outstretched in a crucifix position which gives an indication of your mental state.
'There were defensive injuries to her arms from when she tried to deflect your blows.'
He told the court that Sarrah's cause of death was strangulation and she was found with her cardigan and knickers wrapped around her neck.
Sarrah, 28, who was studying beauty at Newcastle College, hoped to become a celebrity make-up artist or open her own salon in the UK or her native France.
Sarrah, the youngest child of seven, and Gyekye had been in an on-off relationship for about 12 years, the court heard, and moved to Moore Street together in July 2014.
Jolyon Perks, prosecuting, read victim impact statements from Sarrah's brother, Mohammed, and two of her sisters, Kalifa and Salifa.
Kalifa Garba described her sister as a very strong woman, kind-hearted and always caring for other people.
She said: 'Her death affects my ability to think clearly; I feel slow and helpless, which has had an affect on my work.
'The way Sarrah was killed disturbs me and I have regular flashbacks about how she must have suffered before her death.
'I would recall he [Gyekye] once told me all he wanted was to make my sister happy.
'What sort of happiness is this?'
Sarrah's brother, Mohammed, said: 'Right now I think about my little sister every day and am reminded of the conversations we had.
'Missing her is a scar that will never heal. However I still keep a beautiful image of my mother's last child in my mind.
'A little girl who I deeply love who never got angry and had this beautiful quality to forgive others.'
Doctors were unanimous in their view that Gyekye had been suffering from paranoid schizophrenia, Judge Sloan told the court.
Referencing one other incident in which Gyekye had bitten Sarrah's shoulder and put his arms around her throat during a 'play-fight', he said: 'Save for an incident which rose out of play fighting, any violence you have shown in the
past seems to have coincided with psychotic episodes.'