A jury was selected and attorneys made opening arguments Monday in the trial of a man accused of forcing an intoxicated 18-year-old girl to have sex with him in the bathroom of his Casper apartment nearly two years ago.

Michael David Baird is charged with three counts of first-degree sexual assault. He could spend anywhere from 15 to 150 years in prison if convicted on all counts.

Assistant District Attorney Brett Johnson told jurors Monday afternoon the case would likely come down to a question of consent.

Johnson asked jurors, "Is this eighteen-year-old girl who is vomiting going to suddenly decide to have sex with this guy in a bathroom?"

In his opening statement, defense attorney Robert Oldham anticipated "powerful" testimony from the victim, who is expected to take the stand and say Baird forced her to have sex with him.

"There's no doubt sex did take place in that bathroom," Oldham told the jury of nine women and three men. "The only question is, was it consensual?"

According to court documents, the victim told investigators Baird sexually assaulted her on the night of July 27, 2015.

The victim came down to Casper from Worland with two friends -- who were boyfriend and girlfriend at the time but are now married -- who were apartment-hunting.

After seeing a couple of apartments and a making trip to the mall, the group met up with Baird, who was a friend of the boyfriend. Baird and the victim had never met, Johnson told jurors.

The group got a bottle of tequila at Baird's apartment and drank into the evening.

At one point, the victim -- seemingly out of nowhere, Johnson said -- began vomiting and needed a change of clothes. The girlfriend took her into Baird's bathroom, removed her dress and wrapped her in a grey towel.

Then, the girlfriend left to find some clean clothes for the victim, who continued vomiting into the toilet.

According to the victim's statement as presented in a police affidavit, someone entered the bathroom and held the victim's hair back as she vomited. The victim thought it was the woman she drove down with.

The victim turned around, the affidavit says, to see Baird standing behind her, naked. He allegedly shut the door and tried to kiss the victim before trying to force her to perform oral sex on him.

The victim reportedly fought back. Baird gave up and forced her to the floor, the victim told police, where Baird allegedly assaulted her for roughly half an hour.

Eventually, the victim was able to push Baird into a towel rack on the bathroom wall, breaking the towel rack. The side panel of the vanity also fell off, court documents say.

The victim told police the alleged assault ended with one of the people she came to Casper with knocked on the bathroom door. Baird allegedly put a hand over the victim's mouth and nose, holding her throat with his other hand. The victim said she tried to yell, but was unable.

Baird got dressed and left the bathroom. The victim bolted out of the bathroom in her underwear and socks, she told investigators, a few minutes before midnight.

Afterward, Baird's cat reportedly got out of the apartment and the group, including the victim, looked for it. They ended up chasing the cat, which reportedly crawled under a parked car.

It's a detail that will likely be brought up as attorneys explain the scratches Baird reportedly had on his forearms and elsewhere on his body as a result of that night, Johnson said. The victim also suffered a number of scratches on several parts of her body.

Baird faces three separate felony counts -- one each for his alleged attempt to force the victim to perform oral sex on him, his alleged vaginal penetration of the victim and his alleged anal penetration of the victim.

Baird will testify, Oldham told jurors on Monday, because "he was accused of something he says he did not do, and he wants to tell you that."

"He was shocked" to learn of the allegations, Oldham continued. "And he's still in shock as he sits here in this courtroom."

Oldham said when the three of them left Baird's apartment, the couple was under the impression that Baird and the victim had consensual sex -- a fact to which he expects a witness to testify.

When the couple and the victim stopped at a convenience store before returning to Worland, the boyfriend went inside. The victim reportedly disclosed the alleged assault when she was alone with the girlfriend.

The girlfriend then told her boyfriend, Johnson said, and the boyfriend was "livid."

Oldham and Johnson referenced a series of text messages exchanged after the victim and the couple left Baird's apartment that night.

In the text messages, the boyfriend told Baird, "you don't f--- with people I care about." Baird replied, "I'm sorry man," according to the affidavit.

The boyfriend texted Baird, "unforgivable."

But Oldham says at the time the boyfriend sent Baird those text messages, he was unaware of the sexual assault allegation. Oldham told jurors that the boyfriend and girlfriend, when they left Baird's apartment with the victim, had no idea anything besides consensual sex took place in the bathroom.

"[The boyfriend] heard nothing that convinced him otherwise," Oldham said, adding that the boyfriend was upset with Baird because Baird was dating another girl and had seemingly cheated on her with the victim.

But, as Oldham told jurors, "even though Michael [Baird] had a girlfriend at the time, he wasn't worried about her finding out," because the two were in an open relationship. Oldham said Baird's then-girlfriend would testify to support that claim.

Thus, Oldham said, Baird was bewildered by the text messages and replied with several texts saying how sorry he was -- for the perceived infidelity. Oldham says the apologies were in reference to Baird's understanding that he'd been accused of cheating, not sexual assault.

"Michael's shock turned into terror when the police came over and took him downtown, as they say on TV," Oldham told the jury, adding that Baird realized during his police interview that he was accused of sexual assault.

Oldham concedes that Baird lied to police during the interview due to his fear.

After returning to Worland in the early hours of July 28, the victim did not shower and went to Washakie County Public Health for a sexual assault examination the next day, according to Johnson.

Johnson said public health staff referred the victim to the local hospital, as they did not have the means to perform such an examination. The victim reportedly asked public health staff not to report her claim of sexual assault.

But, consistent with their duty, Washakie County Public Health staff called the Worland Police Department to report the disclosure. Oldham said they "did the right thing."

In his opening argument, Johnson acknowledged problems with the subsequent investigation. He made a point of explaining the delay in prosecution, saying DNA samples from the sexual assault examination were not sent to the state crime lab until the fall of 2015.

Results from the state crime lab's analysis were not returned until July 2016.

A lack of recorded interviews may prove problematic in the state's case, Johnson added. He said a recording of one witness interview "does not exist anymore," while an investigator's interview with the victim was not recorded.

However, Johnson said, DNA from both the victim and Baird was found in the victim's underwear.

Oldham noted that based on statements from the victim and one witness, Baird was in the bathroom with the victim for anywhere from 30 minutes to an hour.

"A half hour is a long time," Oldham said, adding that the victim could have yelled for help at any point.

Johnson said during the assault, the victim tried to point out to Baird that he was cheating on his girlfriend and convince him to stop. He allegedly told her everything was fine.

Oldham alluded to "compelling" evidence that will be presented to the jury through Wednesday and pointed to what he says are "major inconsistencies" in the victim's story. He implored the jury to listen closely to what his client and the victim say when they each take the witness stand.

"It doesn't matter what I say about what happened in that bathroom," Oldham said. "It matters what they say."

"The defendant's version of things makes no sense," Johnson told the jury. He concluded by referring again to the series of text messages exchanged after the group left Baird's apartment.

"He didn't say 'I didn't do it,'" Johnson emphasized. "He said, 'I'm sorry.'"