Before returning a verdict of guilty of murder, they must be certain individually, he told the jury, that the accused had the intention to kill, before and during the fatal event, and that she did not do so in lawful self defense.

The jury has been asked to find whether Kissel murdered her husband, killed him in lawful self defense or killed him when provoked into a "sudden and temporary loss of self control," which would result in the conviction of manslaughter because of provocation.

Without a word of introduction or warning, Lunn began the final proceeding after the defense counsel ended his final speech shortly before the lunch break in the High Court Tuesday.

The case began in the early hours of November 7, 2003, when police officers found a rolled-up carpet concealing the decomposing body of Robert Kissel, a former managing director at Merrill Lynch, locked in a storeroom of their luxury Parkview residential complex, said Lunn. A few hours later, Nancy Kissel was arrested for his murder.

In a synopsis of the prosecution case, Lunn said Kissel is accused of killing her husband by "smashing his skull with five separate blows to the upper right side of his head, each one of the blows fatal. Fractured skull bone was driven into his brain."

The prosecution said she was able to do this because he was "sufficiently impaired by a cocktail of drugs," which she served to both him and a neighbor in the guise of a milkshake, said Lunn.

The prosecution wants the jury to take note, said Lunn, of the Internet searches conducted by the accused for drugs and overdoses, and the drugs she was prescribed in the week leading up to the fatal night, the type of which were later found in Robert Kissel's stomach.

Other elements to bear in mind include her amorous relationship with US resident Michael Del Priore, the estimated US$18 million (HK$140 million) estate of Robert Kissel, the defendant's incriminating actions after the fatal incident - including her testimony in court, which the prosecution submits to be evidence of her "spinning a web of lies," said the judge.

The defense, on the other hand, says she killed in lawful self defense when her husband, "following taunting and provocative statements," attempted to force anal sex upon her while threatening her with a baseball bat.

Fearing for her life, she killed him with the metal ornament, originally used to fend off blows from the bat, the defense argues.

Another element to note in the defense case is the allegation that Robert Kissel had "a controlling nature that developed into paranoia," said the judge. Homosexual pornographic Web sites found on the family computer were submitted to support "the defendant's testimony that Robert Kissel routinely forced anal sex upon her."

The judge warned that liars can portray themselves as confident and that "in contrast, those telling the truth, when they present themselves, may be hesitant."

The prosecution does not have to prove a motive in a charge of murder, although it can offer an explanation "to satisfy natural curiosity."

Lunn said it can sometimes be lawful, even "good sense," to kill in self defense, as long as it is with "such force as reasonably necessary to defend [oneself]."

The judge will continue directing the jury today on the evidence from the near three-month trial.