A British psychologist told a Supreme Court jury yesterday that accused murderer George ?Messy? MacDonald Liburd is a sociopath whose severe personality disorder led him to violently kill his former girlfriend Chena Trott.

Dr. Ian Anderson, a defence witness, told the court he interviewed Liburd and gave him psychological tests which indicated the extent of his personality disorder.

As he stabbed Ms Trott repeatedly, Liburd told the psychologist that all her could hear was noise.

?He said forcibly,? said Dr. Anderson, ?that ?all I could hear was noise, it was just noise?.?

Dr. Anderson continued; ?I believe when Liburd was in that situation, on the basis of the information he told me, he was on information overload, he could not process information and he defaulted to the personality disorder which caused him to act as a violent sociopath and to lash out in the violent manner that he did.?

During questioning by John Perry, QC, Dr. Anderson, a chartered psychologist originally from England, told the court that Liburd closely fit all of the academic criteria that psychologists use to diagnose a severe anti-social personality disorder.

?He so closely fits the diagnostic criteria that I could not imagine a reasonable person could not understand,? said Dr. Anderson. ?He has all the problems and attitudes consistent with a personality disorder.?

Liburd, 32, brutally stabbed Ms Trott six times outside the Crawl Esso Tiger Mart as horrified onlookers tried to stop the attack. Liburd, who has a record of criminal convictions including serious abuse of women dating back to 1994, has pleaded not guilty to murder but guilty to manslaughter with diminished responsibility.

The plea means that defence lawyers must convince jurors Liburd suffered from an abnormality of the mind which impaired his mental judgement at the time of the killing.

Prosecution lawyers do not accept the plea, and they maintain that Liburd intended to kill Ms Trott, pointing out that he told Police in the aftermath of the killing that he would kill Ms Trott again if he had the opportunity.

Ms Trott, who had taken out a protection order against Liburd, had been violently abused by him in the weeks leading up to her death, and was staying at the Physical Abuse Centre safe house for women prior to her death on August 9, 2002.

Dr. Anderson told the court that Liburd was violent, had a disregard for the rights of others and for the consequences of his actions, legally and socially.

?He is a person whose mind does not function in the way of an ordinary person, it would be an aberration to describe him as anything but abnormal,? he said.

This week forensic psychiatrist Dr. Paul Harlow also told jurors that Liburd displayed all the traits of a person with an anti-social personality disorder, from his cognitive impairment and low intellectual ability, to his lack of control over his thinking and reasoning processes. He said from a psychiatric perspective, Liburd suffered from a disorder of morbid jealousy ? a disease of the mind which can lead to excessive violence and abnormal behaviour.

However, Dr. Matt Logan, another psychiatrist said Liburd?s killing of Ms Trott was ?a conscious violent act perpetrated by a jealous, controlling and psychopathic individual?.

Dr. Anderson said he did not disagree with that opinion, however, he pointed out that he did not believe the murder of Ms Trott was done to achieve a ?particular goal?.

However, witnesses told the court during the trial that Liburd went to his home before searching for Ms Trott and picked up a raincoat which had a kitchen knife in it. He went with his friend, who was driving him in a car, to several locations searching for his former girlfriend, despite the court order which forbade him from having any physical or telephone contact with her or her children.

Yesterday, Prosecution lawyers challenged Dr. Anderson?s testimony and suggested to the five-man, seven-woman jury that his qualifications and his degree, which is not a doctorate of psychology, are questionable. Dr. Anderson had to give the court an extensive explanation of his thesis and academic background, which was in social psychology, in addition to his experience testifying in trials.

It emerged during the trial that this was Dr. Anderson?s first time testifying in a murder trial, and he had done no formal academic qualification in forensic psychology. He is, however, under the British system, a chartered psychologist and a member of the British Psychological Association, but is not licensed in the US.

Crown prosecutor Carrington Mahoney questioned Dr. Anderson about his experience dealing with accused murderers.

?Have you any experience dealing with offenders of murder?? he asked.

Dr. Anderson said Liburd was the first person accused of murder that he had come into contact with, but he had extensive experience with people suffering from anti-social personality disorders.