The jury in Lyle Howe's sexual assault trial heard forensic evidence as expert witnesses were called Thursday.
Howe has pleaded not guilty to sexual assault and administering a stupefying drug. The charges were laid after an alleged incident on March 20, 2011, involving a 19-year-old woman.
A nurse for the Avalon Sexual Assault Centre, who examined the complainant after the alleged incident, was on the stand Thursday.
Nurse Jane Collins said it was past midnight on March 22, 2011 when she saw the complainant in the Lyle Howe case.
The examination was about 24 hours after Lyle Howe and his friend Jeffery Brown went to the complainant's apartment after taking her out for drinks.
The complainant has testified she woke up naked the next morning with almost no memory of their visit.
During the exam, nurse Collins said the complainant was quiet, and seemed to be in shock.
Collins took photographs of bruises on the complainant's breastbone and breast.
She described other physical signs of possible intercourse, and took DNA swabs from her mouth and genitals.
Collins also gave the complainant a bag to collect condoms from her apartment.
Katharine Murphy, an expert in DNA and comparing bodily fluids, completed an analysis of four condoms and semen found on the complainant's blazer. She explained her findings to the court.
DNA on semen stains on the blazer were found to be from two sources. One matched Lyle Howe. The other matched the complainant.
No semen was confirmed in one condom but DNA found in the second condom matched the complainant and Lyle Howe.
Sexual assault kit swabs collected from the complainant contained only the complainant's DNA.
Murphy told the court the chances of a random DNA match on Lyle Howe were 1 in 490 billion in the white population and 1 in 1 trillion in the black population.
Defence lawyer Mike Taylor asked about whether Collins gave instructions about how to collect that evidence to avoid contamination.
The trial continues Friday.