Neighbors say they saw Brian Laundrie and his parents leave their Florida home with an attached camper after he returned from his trip with Gabby Petito

• A couple said they saw Brian Laundrie and his parents drive off with an attached camper this month.
• A neighbor said they saw Laundrie leave on September 11, the day Gabby Petito was reported missing.
• Laundrie's family told the police last week that they had not seen him since September 14.

A couple who live across the street from Brian Laundrie and his family told Fox News on Wednesday that they saw the 23-year-old and his parents leave their home in a truck with an attached camper about a week after Laundrie returned home alone from a cross-country road trip with his fiancée, Gabby Petito.

Authorities are still searching for Laundrie, who has been missing since last Tuesday and is a person of interest in Petito's death, which has been ruled a homicide.

Charlene and William Guthrie, who moved to North Port, Florida, this summer, said they told authorities they'd seen Christopher and Roberta Laundrie attach what appeared to be a new camper to their truck and drive off for what the Guthries assumed was a weekend camping trip with their son.

"I saw them doing some work. And then when they prepared for their trip, I saw them loading the camper," William Guthrie told Fox.

He said he thought it was odd for the parents to go on a camping trip with their adult son in a small camper.

The Guthries said they reported the incident when authorities came to their home while investigating the disappearance of 22-year-old Petito.

The North Port Police Department and the FBI did not immediately respond to Insider's requests for comment.

Rebecca Ollier, an executive producer at WINK-TV, tweeted on Wednesday that a neighbor said they'd seen Laundrie leave the home with his parents and the camper on September 11, the same day Petito's mother reported her missing. It was unclear whether it was a different neighbor than William or Charlene Guthrie.

Laundrie returned to his parents' home without Petito on September 1. Authorities have said he declined to cooperate during the investigation into Petito's disappearance, and his family said on Friday that they had not seen him since September 14.

Petito's body was found in Grand Teton National Park on Sunday. The FBI said earlier this week that her death had been ruled a homicide.

The police on Monday identified Laundrie's parents' home as a crime scene and searched it.

The search for Laundrie continued on Wednesday, with K-9 units scouring Florida's 25,000-acre Carlton Reserve, where he is believed to have gone missing; his parents said he went there for a hike.