EAGLE — Several expert witnesses took the stand at the Eagle County Justice Center on Thursday in the trial of Justin Cayce Erwin, one of four men accused of sexually assaulting a woman in a Silverthorne apartment on St. Patrick’s Day 2016.

The courtroom heard testimony from the lead detective on the case, the forensic nurse who examined the accuser the day after the alleged assault and an expert forensic toxicologist who reviewed evidence of the case.

Sarah Urfer, the forensic toxicologist, was the first to testify. Urfer was working with the Colorado Department of Investigation at the time of the incident and was asked to review the evidence collected from the accuser’s sexual assault nurse examination. She also studied the four videos that were taken of the alleged assault to look for clues to determine levels of intoxication of the woman and men involved.

Urfer testified that the woman appears to become more intoxicated as the videos progress, showing significantly more signs of inebriation in the fourth video than the first, which were taken about 58 minutes apart. The woman’s level of debilitation during the incident has been a key point throughout the trial and will ultimately be a deciding factor in determining whether or not she was able to consent to the group sex acts that took place in the early morning of March 18.

Urfer reported that the woman was clearly conscious in all four videos, but showed other signs of drunkenness, including slurred and repetitive speech, slow reaction times and uncoordinated movement. Erwin can be identified in all four videos.

“That behavior in its totality is consistent with her being impaired,” said Urfer. “Significantly.”

Urfer confirmed that the woman was on a prescribed generic form of Prozac at the time. She noted that the drug mixing with alcohol usually doesn’t create a strong reaction, but it could potentially “exacerbate the intoxication.” Urfer also analyzed the footage of Erwin to determine his level of intoxication, but said she was unable to come to a conclusion.

The amount the accuser had to drink that night has been brought up numerous times during the trial, and is fairly well documented through about 2 a.m. Urfer said that the amount the woman purportedly drank — five to six alcoholic beverages — wouldn’t have accounted for the intoxication noticeable in the videos, taken between 3:56 and 4:48 a.m. There were no signs of date rape drugs or any other similar substances based on toxicology reports taken during the sexual assault exam.

Krista Hyde, the nurse who delivered the exam, was the next to testify. She detailed literally dozens of injuries the woman sustained during the night, primarily bruises and scrapes, over her entire body. She also noted vaginal tearing; something she said was very rare in consensual sex.

Both Hyde and Mary Skowron, coordinator of St. Anthony Summit Medical Center forensic nurse examiner program, said that this many injuries from a single incident is exceedingly rare. “The amount of injuries that I documented on this was substantially more than I, to date, have documented on any patient I’ve seen,” said Hyde. “It’s not something that we see.”

In a bizarre twist, all of the photographs taken during the examination — what would have amounted to hundreds — were lost by the hospital. Only two photographs that the accuser took herself on the morning of the 18th were submitted into evidence.

Detective Theresa Barger of the Silverthorne Police Department also returned to the stand to testify. Barger is also working as a consulting witness for the prosecution on the case.

She provided the jury with details of her investigation, from collecting DNA evidence to interviewing suspects. It was during the execution of a search warrant for the alleged crime scene where much of the evidence was uncovered.

The alleged assault took place in Ramon Villa’s apartment, another of the accused. During the search, Barger collected Villa’s cellphone — which eventually revealed the four videos of the incident as a keystone piece of evidence — along with Erwin’s wallet that he reported missing and found, the accuser’s underwear and more. Villa refused to give the passcode on his phone to law enforcement and it was sent off to Dixie State University in Utah where experts were able to download its contents.

A video of an interview between Barger, Erwin and Silverthorne Police officer Joel Ponedel, who also investigated the incident, was shown to the jury. In the video, Erwin’s responses to the officers’ questions stray wildly from other witnesses’ testimonies and subsequent evidence collected.

Erwin was questioned about his wallet, the accuser and his activities that night. In the video, Erwin maintains that he has no idea how his wallet would have ended up in the apartment, that he had no idea who the accuser was and that he walked to his girlfriend’s residence that night. He also noted that he had never been to the apartment in question before.

The videos captured of the alleged assault clearly place Erwin in the apartment. His date on St. Patrick’s Day also claimed that they had both been in the apartment numerous times before and that Erwin never came to her apartment that night. Bartenders who served Erwin that night also testified that he interacted with the woman at the bar and that the two left together.

The trial will resume on Friday morning at 8:30 a.m. with the defense’s cross-examination of Barger.

Two of the cases from the alleged assault have already been adjudicated. Paul Garvin was convicted of a Class 2 sexual assault in Summit County District Court in October last year. Michael Gelber pleaded guilty to a reduced felony charge and two misdemeanors last month. Villa pleaded not guilty to felony charges in December, and will head to court in Eagle in September.