• William Guthrie said it was "odd" that the Laundries would go camping with their adult son in a "small" RV
  • Brian was also seen getting very "aggressive" at a restaurant on Aug. 27
  • Gabby Petito's body was found in a forest Sunday

YouTuber Gabby Petito's boyfriend Brian Laundrie and his parents were seen driving off hitching an "attached camper" the same day Petito was reported missing, a couple who lives across the Laundrie family's home in Florida has claimed.

The neighbors, Charlene and William Guthrie, said the Laundries hooked what appeared to be a new camper to the back of their truck and drove off for a weekend trip, reported The New York Post.

William said he was in his yard on Sept. 11 when he saw Brian and his parents – Christopher and Roberta – driving off for the weekend trip.

"I saw them doing some work. And then when they prepared for their trip, I saw them loading the camper," he said, adding that he found it odd that Christopher and Roberta would go camping with their adult son in a "small" RV. 

The 22-year-old YouTuber was reported missing on Sept. 11, while on a cross-country road trip with Brian, who returned to Florida three days later. Her body was found in a forest in Wyoming on Sunday.

The Guthries initially assumed that Petito was with Brian when he returned to the family home on Sept. 14 in a white van. They only knew about her disappearance after finding the street occupied by reporters, police and protesters.

"We didn't know it [the van] was Gabby's, we just assumed it was [Brian's] van. We just thought they had come back from wherever. We didn't know they were on a trip. We assumed they went back to their house or wherever they got a house … We didn't know much about them at all," Charlene said.

The Guthries, who moved to North Port recently, said it was a "nightmare" to live in the neighborhood amid the high-profile investigation and media circus surrounding the Long Island native's death.

A WINK-TV journalist tweeted Wednesday that a neighbor saw Brian and his family leave with the camper on Sept. 11, the day Petito was reported missing. The neighbor, however, did not know if Brian returned home or not.  

Brian's parents reported him missing on Sept. 17, three days after they said they last saw him. 

Brian reportedly got very "aggressive" with the employees at the Merry Piglets restaurant in Jackson Hole, Wyoming, during the couple's ill-fated cross-country trip. This was just two days after Petito last spoke to her mother. Petito had to apologize for her boyfriend's behavior at the time. Her mom said she got an "odd text" from her daughter's phone the same day.

"I have chills right now," Nina Celie Angelo, who witnessed the incident, said. "It's crazy because it wasn't just like we passed them on the street. It was a full-blown incident."

Angelo said she was at the Tex-Mex eatery around 1 p.m. on Aug. 27 when she saw Brian "aggressively" arguing with the restaurant staff about the bill. Brian then stormed out of the restaurant, while Petito later came in and apologized for his behavior.  

gabby petito Gabby Petito was last seen on Aug. 24. Photo: Suffolk County Police Department