An 18-year-old woman was still alive when her boyfriend started to cut off her head with a knife, a jury has been told.

Aras Hussein, 21, killed Reema Ramzan by decapitating her at his flat in Sheffield before stabbing himself in the chest, the city's crown court heard today.

Prosecutor Graham Reeds QC told jurors about the wounds Miss Ramzan suffered at the hands of her Iraqi-born boyfriend on June 4, last year.

Mr Reeds said: "Bruising into tissue wounds suggest that Reema was still alive as the defendant started to remove her head.

"The process of decapitation would require considerable motion with corresponding considerable force which needed to be sustained until all the tissues had been cut through.

"Force would also be needed to restrain the victim who is likely to have been struggling.

"Severe force would have been needed to cut through the spinal vertebrae with a knife in order to remove the head."

Mr Reeds told the jury: "No-one can know what happened in that room immediately before the killing and what led to it."

He said Hussein was spotted naked outside his flat in Herries Road, Sheffield, with blood pouring out of his chest.

The prosecutor said the defendant told emergency workers who came to his aid: "I don't know why I did it."

He said Hussein told the paramedics: "She like me but I raped her. What I did was wrong. I need punishing for it."

And he told them: "Why are you helping me? I've murdered someone."

Hussein sat in the dock listening to Mr Reeds open the case for the prosecution, wearing a grey waistcoat, white shirt and striped tie and surrounded by guards.

He denies murder.

Mr Reeds told the jury Hussein is likely to claim he was suffering from diminished responsibility at the time of the attack due to schizophrenia.

Mr Reeds described how Miss Ramzan lived with her family in the Darnall area of Sheffield.

He said her family disapproved of her relationship with Hussein and the prosecutor outlined a series of incidents when her relatives had come into conflict with the defendant.

Mr Reeds told the jury about one occasion when police warned Hussein after he took sexual pictures of Miss Ramzan and threatened to show them to her family if she ever left him.

He said: "This demonstrates his attitude towards her."

Mr Reeds outlined another incident when Miss Ramzan's brother Sohail argued with the defendant after spotting red marks around his sister's neck.

He said Hussein told her brother that "he'd do what he liked".

The prosecutor said that what was known about the day Miss Ramzan died was that she went to Hussein's flat with her passport and a large amount of money.

He said: "She did not tell anyone from her family she was going there.

"She did not tell anyone why she had her passport and this money with her."

He said a neighbour of Hussein's heard a woman "screaming for dear life" that afternoon.

Mr Reeds said the defendant stabbed himself in the chest with a large kitchen knife, removed his blood-stained clothes and went outside.

Another neighbour who saw him in the car park thought he had been shot.

He was spotted naked, holding a wad of money and his passport in his hand.

The prosecutor said that Hussein was calm when he was first arrested but after he was taken to the nearby Northern General Hospital for treatment he attacked staff trying to help him.

Mr Reeds told the jury of eight women and four men how the defendant attacked a cardiothoracic surgeon and an anaesthetist as well as police officers who tried to restrain him, one of whom was bitten.

He told the court how Hussein was only subdued after he was injected with a sedative.

The jury was told the defendant denies a number of counts of assault occasioning actual bodily harm in relation to these alleged attacks at the hospital.

Mr Reeds said the prosecution rejected Hussein's likely defence of diminished responsibility.

He said he had "no history of mental illness".

"He was able to function perfectly well - he held down a job, he lived on his own, he had his own flat and, it's a self-evident truth, he had a girlfriend."

Mr Reeds said: "The prosecution case is that his behaviour right up until the time of the killing was entirely ordinary.

"Of course the killing itself was anything but ordinary."

He said: "The prosecution say that his behaviour at the time of the killing is much more likely to be explained by the fact he had a propensity towards violence and his controlling behaviour towards Reema."