Doctor's rape trial: DNA evidence may have been washed off, diluted
Tests done by the Health Sciences Authority (HSA) on the underwear of a 26-year-old woman who is accusing her doctor of molest and rape have shown no traces of semen, with insufficient DNA detected.
Swabs done on the woman's vagina also tested negative for traces of semen, a court heard yesterday.
HSA analyst Tan Ying Ying was one of four witnesses called to the stand on the fifth day of the trial of Wee Teong Boo, 67.
He is accused of molesting and raping the woman, then a 23-year-old student, during two visits in late 2015. She cannot be named due to a gag order.
The court heard that the alleged victim's underwear had been soaked in a pail of water for at least 11 hours before it was seized by the police and tested by the HSA. She wore the underwear when the alleged rape took place in the early hours of Dec 31, 2015.
Ms Tan said that in general, soaking can lead to a loss of DNA and semen.
As there was a brown stain on the woman's underwear, it was also tested for blood as a matter of procedure. The test came back negative. Ms Tan clarified that this does not rule out the possibility that the stain was blood as it might have been too diluted to be detected as such.
The woman had also washed her vaginal area with soap and water after the alleged offence. When asked if that would affect the results of the swab, Ms Tan said: "In general, washing can lead to a loss of semen."
Examinations were also done on the shirt, pants and underwear that Wee was said to have worn at the time of the alleged rape.
But tests for DNA were inconclusive as multiple sources of DNA were found on all pieces of his clothing.
The examination bed in Wee's clinic, where the alleged rape took place, was also swabbed and tested for blood and DNA. The results were negative and inconclusive due to multiple DNA profiles belonging to at least four people.
These DNA profiles cannot be pinpointed as belonging to either the alleged victim or Wee, the court heard.
The swabs, the clothing and the underwear were all taken on the afternoon the woman made a police report against Wee on Dec 31, 2015.
Wee has pleaded not guilty to one count each of rape and molestation.
The trial continues tomorrow when Dr Janice Tung, who examined the woman and found a fresh tear in her hymen, is expected to take the stand.