Groomsmen and bridesmaids passed around beers and shots of vodka as they guided paddle boards and rafts downstream.
When they returned to their hotel on 30 August, Daniel Carney’s wife-to-be asked him to walk a friend inside.
The 29-year-old Oregon woman had been too drunk to keep her balance on her paddle board, the Morning Call reported, and as Mr Carney walked her down the hallway, she swayed and struggled to stay upright.
Suddenly, Mr Carney pulled the woman into the men’s locker room.
Then, police say, the groom led the woman to the showers, where he forcibly grabbed her, bit her and removed her bikini bottoms.
That’s when the bride walked in.
On Thursday, prosecutors charged Mr Carney, 28 of Stroudsburg, Pennsylvania, with felony sexual assault, according court records.
Pennsylvania State Police say it used security footage, text messages and an intercepted phone call to support the bridesmaid’s allegation that she had been sexually assaulted while “blackout” drunk.
As the groom scrambled to explain his behaviour, the wedding itself somehow went on as planned, local TV station WNEP reported.
“It was chaos amongst the entire wedding party,” the woman told police, the Morning Call reported.
Two very different stories emerged from the wedding party about the locker room encounter at the red-roofed Shawnee Inn and Golf Resort, tucked into a lush wooded hillside on the riverfront in Monroe County, Pennsylvania.
The woman later told police she could only remember snippets of the night, and could not recall much of the alleged assault, but she was certain she had been violated.
She told police she’d had three beers and one or two shots of vodka to drink that day, and had splashed into the water several times before floating the rest of the journey on the group’s raft before Mr Carney led her into the hotel.
The victim told police she woke up briefly on the floor of the locker room to a sharp pain as Mr Carney allegedly bit her and pawed at her body.
She said she passed out again, only to wake up minutes later to realise her bikini bottoms had been removed and Mr Carney was on top of her.
Twenty minutes later, police say, his fiancee burst into the men’s showers. The bridesmaid told police her friend immediately started screaming at Mr Carney.
The bride followed him into the parking lot and the two got into a physical fight, according to court records.
Another bridesmaid helped the woman walk out of the showers, the Morning Call reported.
The next morning, Mr Carney called the bridesmaid to apologise, but claimed he didn’t know what they had done the night before, according to the police report.
On the morning of the wedding, he texted again to ask the woman to put on a good face for the wedding and to pressure her to take the morning after pill to prevent an accidental pregnancy.
“I wanted to apologise again for everything,” he wrote in a lengthy message, according to the probable cause affidavit.
“Can we please just be as happy as possible for [the bride] today? Mistakes are behind us and I just need total closure before I do this [that is] why I’m sending this.
“I’m as happy as ever to marry [the bride] and I know this is terrible as well but my d*** was out in the shower.
“We never did do it but would you consider taking plan b to make damn certain just in case? There is almost no chance but still. Please tell me yes I’m begging you.”
Despite the shocking incident, WNEP reported, the couple still got married on 1 September.
But the next morning, the bridesmaid went to the hospital to report that she’d been sexually assaulted. She told police she felt “extremely violated and upset”.
Mr Carney, meanwhile, allegedly told his guests the woman had “followed him” into the locker room after he told her he was going to shower. He later told a state trooper he was extremely drunk and felt she had “taken advantage” of him.
But police say a clearer picture of the night began to emerge after they pulled security footage from the hotel.
“The footage showed the victim and the accused walking down the hallway, with the victim extremely unsteady on her feet and swaying,” state trooper Justin Leri wrote in a police report.
“Just before the doorway, the accused is observed turning around and pulling the victim into the locker room.”
That’s where the reach of the hotel’s security cameras stop, according to a probable cause affidavit reported by WNEP.
After police reviewed the video, Mr Carney changed his story, admitting he’d grabbed the woman by the arms and pulled her into the locker room.
Police then intercepted a second call between Mr Carney and the bridesmaid, during which he claimed they did not have “actual sex”, but “repeatedly told her he was sorry, specifically repeating that it was all his fault”.
He also admitted to leading the woman into the locker room during the phone call, the Morning Call reported.
Prosecutors charged Mr Carney with simple assault, indecent assault and involuntary deviate sexual intercourse of an unconscious person.
An arraignment has not yet been scheduled for Mr Carney, and his case is awaiting a preliminary hearing. His lawyer did not immediately return a request for comment late on Sunday night.