A government chemist yesterday told a jury he did not report on the quantities of drugs found in Robert Peter Kissel, who was allegedly murdered by his wife, because it would have been misleading.
Cheng Kok-choi, who identified four hypnotics and an anti-depressant in the senior Merrill Lynch banker's stomach and liver, was asked by prosecutor Peter Chapman to respond to a series of criticisms of his findings by Olaf Drummer, a forensic expert from Australia called by the defence.
Responding to criticism that the amount had not been quantified, Dr Cheng explained that the banker's body had already started to decompose when it was found on November 7, 2003, five days after he was allegedly bludgeoned to death after being served a sedatives-laced milkshake by his wife, Nancy.
'It is a well-known fact in the case that the [quantitative] results would not be reliable and can even be misleading,' said the prosecution witness. He said such results would only be sought on special request from the government laboratory or in cases of drug overdose. He said he had only been sent 20 millilitres of stomach contents - rather than a whole stomach, which would have been needed for the quantification.
The drugs found were Rohypnol, Lorivan, Ambien, Axotal and amitriptyline.
Mr Justice Michael Lunn asked the witness if the amount of drugs found corresponded to 'a tiny fraction of a normal dose'. The witness said yes.
Nancy Kissel, 41, has pleaded not guilty to a count of murder.
Professor Drummer also said in his written report that traces of drugs found in the deceased's stomach did not necessarily mean they were consumed orally.
He said they could have been caused by a contamination of stomach contents by bile or vomiting. Responding to this, Dr Cheng said: 'This statement is true. I did additional tests and concluded that these [possibilities] cannot be excluded.'
The Australian expert detected one of the hypnotics, Ambien, from his test on the deceased's hair sample and concluded that Kissel had been taking Ambien for two to three months before his death.
Agreeing with Professor Drummer's conclusion, Dr Cheng told defence counsel Alexander King SC that the deceased seemed to be using the drug habitually.
But the witness said he did not agree with the professor's suggestion that the drugs had been in Kissel's stomach much longer than usual, saying there was no basis to say there was an abnormality.
In cross-examination, Mr King said that in the chemist's written reply to Professor Drummer in June, there was 'a large measure of agreement' between the experts.
The judge asked the witness if he detected any presence of cocaine in his screening test for other drugs and poisons. Dr Cheng replied: 'Unless you have taken an overdose of cocaine, you cannot detect it in the liver.' He explained that cocaine would be hydrolysed in the stomach because of the acidic nature of the gastric juice.
Asked by Mr King if any hydrolysed product of cocaine was found in the stomach sample, the witness said no. But he said there was no universal screening procedure that could 'detect everything under the sun'.
The case continues today.