He is alleged to have strangled and stabbed the Chinese national in the massage parlour she ran in Ang Mo Kio.
Earlier, a forensic scientist testified that the blood-flow pattern at the scene indicated that she was likely on her back when she was stabbed.
A forensic pathologist also said that it was difficult to conclude whether the accused stabbed himself to cover up the murder or if he sustained his nine stab wounds during their struggle.
If convicted of murder, he faces the death penalty.