Blood on Courtney Pieters' jeans, panties doesn't necessarily mean she was raped - defence (Warning: Sensitive details)

Blood found on the panties and jeans of three-year-old Courtney Pieters did not necessarily indicate that she had been raped, the advocate representing murder accused Mortimer Saunders said in the Western Cape High Court on Wednesday.

There was a possibility that the stain was caused by purge fluid released during decomposition, defence advocate Mornay Calitz pointed out to State witness, Warrant Officer Hildegarde Thunemann-Olah of the police's forensic science laboratory.

Thunemann-Olah, an evidence recovery analyst, said she could not testify about this.

The warrant officer, who recovered the biological evidence, conducted presumptive tests on the little girl's green panties, blue embroidered jeans and white short-sleeved top. Multiple swabs were taken.

She explained that she used Hemastix to test possible blood which was visible, luminol for possible invisible blood and a reagent to check for semen.

She said there was visible blood on the crotch area of the pants and underwear, which, to her, indicated a possible sexual act.

Read: Delay in testimony of pathologist who examined Courtney Pieters

Pieters' decomposing body was discovered in Epping Industria in May, nine days after her disappearance from her Elsies River home.

Saunders faces charges of premeditated murder and rape but denies that he planned the toddler's death or that he raped her while she was alive.

In his plea explanation, he confessed to murder and to using his fingers to penetrate her after her death.

Saunders said he had given Pieters ant poison to make her sick, before he choked her, beat her and used a towel to close her mouth.

He claimed he had done it because of "ill feelings" between him and her mother, Juanita.

Saunders - a childhood friend of Pieters' father who lived in the same house - had also apparently been irritated because the toddler wanted to watch TV in his room and he wanted to sleep.

Pathologist Professor Johan Dempers, who supervised the little girl's post mortem, previously testified that Pieters had died as a result of asphyxia through smothering or strangulation, "and/or" poisoning.

She had also sustained external blunt-force injuries to her face, torso and limbs, and there were signs of pressure to her neck as well as genital injuries, Dempers said at the time.

He added that the genital injuries could have been caused by it being overextended.

When asked during his evidence-in-chief if he could say whether she had been raped before she was killed, Dempers said he could not exclude that her injuries happened ante-mortem.

The case was postponed to Tuesday, when the State and the defence are expected to argue over whether the prosecution should be allowed to lead evidence after "further scientific developments" came to light.

Read more: Courtney Pieters murder: 'Further scientific developments' lead to postponement of trial

This is understood to be related to the alleged rape and whether it was committed before or after her death.

Calitz said the tests were conducted by Dempers after his evidence-in-chief and objected, as it "wasn't evidence not led by oversight".