Government chemist Lun Tze-shan explained that, by taking photographs of the pattern, size and shape of blood and the height at which the splatters landed in the master bedroom, it can be estimated what might have taken place, what kind of weapon was used, and the posture of the victim when he was attacked.

Nancy Kissel, 41, is accused of drugging her husband with a milkshake laced with sedatives, leaving him unconscious at the foot of their bed as she beat him to death with a heavy metal ornament on November 2, 2003.

The accused told a doctor and the police at the time that her drunken husband assaulted her, and then disappeared. She denies the murder charge and is out on bail.

The banker's decomposing body was discovered in a storeroom in the Kissels' Parkview residential complex in the early hours of November 7.

``From the distribution of bloodstains - on the surface of the television, cabinet and end of the bed [which were] basically found at a low level - my finding is that the attack could have happened at the end of the bed or the surrounding area,'' Lun said.

He said he thought blood splashed from the wound and landed on various items because he found no ``contact blood.'' In other words, there was no evidence that blood was smeared on surrounding items due to a struggle, he said.

If a long weapon had been used in the attack, the flinging action would have left ``cast-off blood'' in the area, but he found no evidence of such a pattern. As the blood stains were generally found at a low level, Lun believed the victim could not have been standing when he was attacked.

Blood stains on a cushion, which was found packed in a cardboard box, exhibited the ``impact pattern,'' but since the cushion was not found in the master bedroom, he could not be sure if it was related to the same attack.

DNA tests on samples from the blood spots found at the foot of the bed showed they probably came from the deceased banker, but DNA results ``are expressed in probability,'' Lun said.

However, no results were obtained from the DNA analysis on a stain found on the headboard of the bed.

``I cannot even tell whether or not it was a blood stain,'' said Lun.

Under cross-examination, senior counsel Alexander King for the accused pointed out there were other blood spots in the region at the head of the bed, that Lun had consciously omitted from his ``expert's report'' in June, 2004.

Lun went to the murder scene on November 8 to conduct the ``blood-stain pattern analysis'' after a police officer, who conducted the preliminary examination, informed him of the blood stains on various items around the room.

King pointed out in photographs, blood spots on a photo frame, which Lun agreed he had consciously omitted from his ``expert's report'' and did not submit for DNA testing.

``Did you find any other blood in that location [the head of the bed] that you did not bother to record?'' asked King.

``According to my memory, there was a small amount of blood spots on the table and dehumidifier that I did not choose for DNA analysis [because I thought they were all part of the same pattern],'' Lun said.

The trial continues today.

albert.wong@singtaonewscorp.com