A hiker who happened to resemble Brian Laundrie -- the fiancé of Gabrielle 'Gabby' Petito and a person of interest in her death -- was reportedly ambushed by U.S. Marshals after being mistaken for the missing 23-year-old.

Severin Beckwith, of Ithica, New York, told the New Yorker that he and girlfriend Anna Brettmann were napping at a Lodge at Fontana Village Resort, where they were staying amid a hike from Georgia to Virginia along the Appalachian Trail that began in late September, when they were awoken by authorties.

“Next thing I see is a bunch of guys with riot shields with ‘U.S. Marshals’ written on them,” Beckwith said. “Handguns pointed at my face.”

Brettman was still in bed when the feds ambushed Beckwith, who said he was handcuffed while still in his underwear and taken out to the hallway, noting that he had a hunch as to why he was mistakenly being arrested.

“I really hoped I was right,” Beckwith said.

Additionally, Brettman and Beckwith booked the hotel using a credit card connected to a New York State ID, which tied into Petito being a native of Long Island.

Fortunately, Beckwith was quickly cleared as he didn't have Laundrie's tattoos and showed legitimate identification.

Beckwith said U.S. Marshals advised him to shave his beard, which he quickly regretted doing, "because I have much less of a chin than Laundrie does."

The couple said they were given a complementary hotel buffet breakfast for their troubles after the incident.

Last week, Teton County Coroner Dr. Brent Blue announced Petito's cause of death was ruled as a death by strangulation and the manner of death to be a homicide during a press conference.

Dr. Blue said Petito's death is believed to have occurred 3-4 weeks prior to her remains being found on September 19 and confirmed to match her days later.

Dr. Blue confirmed the ruling was made while working alongside local and federal authorities. No other information will be released in adherence with state law.

Laundrie is currently listed as the sole person of interest in her death and is the center of a publicized search by the Federal Bureau of Investigation and local authorities at the Carlton Reserve campsite in Venice, Florida.

Dr. Blue said local law enforcement would decide who would be charged in connection to Petito's homicide case.

Laundrie's parents said their son was last seen hiking in Carlton Reserve on September 13 after he returned to Florida from a cross country trip without Petito.

On October 7, Chris Laundrie, Brian's father, joined authorities in their search of Carlton Reserve for his son, according to family attorney Steven Bertolino.

Remnants of a campsite that appeared to have been recently used were reportedly the focus of the search, a source close to the Laundrie family told CNN's Chris Cuomo last Wednesday (October 6).

On October 5, Laundrie's sister, Cassie, said she doesn't know where her brother is and would "turn him in" if she did in an exclusive interview with ABC News.

Cassie Laundrie said she last heard from her brother on September 6 -- after he returned from his cross country trip without Petito -- when the family went to Fort De Soto Park in Pinellas County, Florida.

"We just went for a couple of hours and we ate dinner and had s'mores around the campfire and left, and there was nothing peculiar about it," she said. "There was no feeling of grand goodbye. There was no nothing."

"I'm frustrated that, in hindsight, I didn't pick up on anything," she added. "It was just a regular visit."

Cassie added that it's unusual for Brian to disappear this long, having initially been reported missing on September 17, days after Petito's parents initially reported her missing.

"I worry about him. I hope he's OK, and then I'm angry and I don't know what to think," she said. "I hope my brother is alive because I want answers just as much as everybody else."

Cassie said she's cooperated with authorities during their investigation "since day one" and believes her parents should do the same, noting that she's unsure of their role.

"I don't know if my parents are involved," she said. "I think if they are, then they should come clean."

On September 30, police released additional bodycam footage which shows Petito telling an officer that an argument with Laundrie got physical.

The newer footage stems from the incident on August 12 in Moab, Utah in which police made contact with Petito and Laundrie after a bystander called the Moab Police Department and reported seeing a man hitting a woman.

WRAW Newsroom