Janet Hall was called to give evidence by the defence team of the Ulster and Ireland fly half Paddy Jackson.
The officer then examined the alleged victim's clothes, which included underwear; a pair of white jeans - "grubby and stained" - with blood marks visible on the outside; and a black sequin-covered sleeveless top. A scientific officer with Forensic Science Northern Ireland described how she had used swabs taken from Mr Jackson, Mr Olding and Blane McIlroy, who is also on trial accused of exposing himself to the complainant, in order to create a DNA profile of them.
However, she also said while bleeding injuries "are not common in this type of case", she had in the past referred two such cases for treatment in hospital to stop the bleeding.
The jury of nine men and three women heard details of forensic evidence and was shown photographs of the clothing worn by the woman on June 28, 2016.
The woman's blood was also detected on the crotch area of the pants, the court heard.
When Hedworth asked "was blood staining visible on that?", she answered "yes". All of the blood analysed was found to be that of the complainant.
However, there was blood matching the alleged victim on the swabs.
The complainant's trousers were also blood-stained, with the expert determining that one stain bore a "transfer pattern".
Earlier today, a leading forensic medical expert voiced concerns over the finding of an internal injury in the young woman some 14 hours after she claimed she was raped. "If you see it in front of you, you know what you are looking at".
However, the doctor claimed the video in this case "did not show me where the laceration was.it was just a pool of blood", and went on to explain there was no note of whether or not the blood was the result of menstrual flow, which could be intermittent.
Mr Kelly asked Dr Hall after hearing the examining doctor's evidence, what comments would she make on the source of blood.
Dr Hall said: "From my perspective, I didn't see the injury". I think I would have been thinking along the lines of how I would have stopped the bleeding.
Dr Hall later added: "It leaves a question in my mind, could it still be menstrual".
She told the court she had reviewed the notes and a video of the examination carried out by a doctor at the Rowan sexual assault referral centre at Antrim Area Hospital, in which he documented an internal tear which he said had been caused by blunt force trauma.
Dr Hall replied: "The evidence overwhelmingly is that it's allowed to happen". "And, as I have said before, be on your guard".
The doctor went on to agree with Kelly that it was "hard to believe there were injuries inside, and not injuries on the protective outside" in cases of excessively forceful or violent rape, although in cases of digital penetration there was a "risk" of injury occurring.
Two other men are also charged in connection with the incident.
Defence QC Arthur Harvey for Blane McIlroy (26), who along Rory Harrison (25) is also on trial facing lesser charges, asked about the affects of alcohol on a person's behaviour.