A couple of days after she was allegedly raped by her half-brother, an intellectually disabled teenager, 18, had sex with a stranger she met at a park.
The High Court heard this on Monday as the trial of the 39-year-old half-brother began.
The man had pleaded guilty last year to raping and sodomising his half-sister at his one-room flat over a period of two nights in March 2010.
But he withdrew his plea in February, claiming that he was innocent, and he admitted to the charges only to "save his wife".
The parties in the case cannot be named to avoid identifying the alleged victim.
The accused and the girl have the same mother. In 2006, she moved in with another half-brother.
In March 2010, she was sent to stay with the accused following an argument with her other half- brother and his wife.
The prosecution's case is that over the next two nights, the accused violently sexually assaulted her. The girl later fled the flat and told her stepfather that she had been raped.
Yesterday, two psychiatrists from the Institute of Mental Health took the stand - Dr Rajesh Jacob, who had assessed the girl's intelligence, and Dr Alvin Liew, who had interviewed the accused after his arrest.
Dr Jacob said the girl could give basic details such as time and place and do simple calculations but had difficulty answering long questions, and had limited proficiency in English.
He said she became emotional when talking about the alleged rape, so he did not probe further. She also told him she had no prior sexual experience.
Defence counsel S.K. Kumar then told the psychiatrist that the girl had an abortion in 2009.
He also told Dr Jacob that one or two days after the alleged rape, she had sex in a hotel with a stranger who approached her. The lawyer suggested that she would not have done this if she had been sexually abused.
Dr Jacob said: "It is highly unlikely for a person to have sex one or two days after a traumatic event."
Mr Kumar noted that the girl had lied to Dr Jacob about her sexual history and had also lied to the stranger about her age. "She's capable of twisting the facts when it suits her," he said.
When questioned by Deputy Public Prosecutor S. Sellakumaran, Dr Jacob agreed that a person with low intelligence is more easily induced into agreeing to sex if offered money or food.
It also emerged in court that the accused's wife had given contrasting accounts of events.
She told Dr Jacob that she was not aware of the incidents but told Dr Liew and the police that she witnessed her husband committing acts of rape.
The trial continues today.
