Cardiff prison attack inmate Colin Capp was 'mentally ill'
An inmate who stabbed his cellmate to death with a pen at Cardiff prison was suffering from paranoid schizophrenia, Cardiff crown court has heard.
Colin Capp, 23, of Scotland, attacked Darren Thomas, 45, while he slept in their cell on Wing B.
Consultant forensic psychiatrist Dr Melanie Croy told the jury Mr Capp's ability to form rational judgement was impaired because of his mental illness.
Mr Capp admits killing Mr Thomas but denies murder.
Appearing for the defence, Dr Croy, who works at Ashworth high security hospital where Mr Capp has been detained, said he suffered from an abnormality of mental function, which could diminish his responsibility for Mr Thomas's murder.
Dr Croy told the court Mr Capp suffered from paranoid delusional beliefs and heard two voices in his head.
One, which he describes as Mr Grey, tells him to harm others and himself, the jury was told.
Since he has been at Ashworth hospital, Mr Capp has described voices telling him to kill others with his bare hands, she said.
A second female voice acts as a guardian and gives him advice, the court was told.
Mr Capp told Dr Croy he believed he was being tortured at Cardiff prison in the weeks leading to the killing and thought he was going to be killed.
A different consultant psychiatrist, on behalf of the prosecution, believes Mr Capp has a personality disorder rather than a mental illness.
Dr Phillip Joseph told the jury he believed Mr Capp understood what he was doing when he killed his cellmate.
MrThomas was discovered dead in the cell with a plastic bag wrapped around his head. He had been stabbed 100 times in the neck with a ball point pen.
Mr Capp denies murder on the grounds of diminished responsibility.
The trial continues.