ST. PETERSBURG, Fla. — A Florida woman who vanished while on a nomadic cross-country trip in a converted camper van with her boyfriend is the subject of a nationwide search while authorities labeled him Wednesday as a person of interest in her disappearance.

Investigators say Gabrielle “Gabby” Petito, 22, was last in contact with her family in late August when the couple was visiting Wyoming’s Grand Teton National Park. Much of their trip was documented on social media accounts that abruptly ceased.

The boyfriend, Brian Laundrie, returned to their Florida home in her 2012 white Ford Transit van on Sept. 1 — 10 days before Petito’s family reported her missing — according to police in the Gulf Coast town of North Port. That van has since been impounded by investigators and processed for clues.

Laundrie has not cooperated with police and is now considered a person of interest in the case, North Port police said. He has not been charged with any crime; the FBI and the Suffolk County Police Department in New York are assisting in the investigation.

“We are pleading with anyone, including Brian, to share information with us on her whereabouts in the past few weeks,” North Port Police Chief Todd Garrison said in a statement Wednesday. “The lack of information from Brian is hindering this investigation. The answers will eventually come out.”

An attorney for the Laundrie family, Steve Bertolino of New York, said in an email Wednesday that the family “is remaining in the background” as the search continues and will have no further comment.

“In my experience, intimate partners are often the first person law enforcement focuses their attention on in cases like this and the warning that ‘any statement made will be used against you’ is true, regardless of whether my client had anything to do with Ms. Petito’s disappearance. As such, on the advice of counsel Mr. Laundrie is not speaking on this matter,” Bertolino said.

Petito and Laundrie were childhood sweethearts in Suffolk County but moved from Blue Point, New York, in 2019 to live with his parents in North Port, which is about 34 miles south of Sarasota. They set out on their journey in July from New York, saying on social media accounts they intended to reach Oregon by Halloween.

“At no point in my investigation did Gabrielle stop crying, breathing heavily, or compose a sentence without needing to wipe away tears, wipe her nose, or rub her knees with her hands."

- Officer Daniel Robbins, in his report

An eight-minute YouTube video titled “Van Life: Beginning our Van Life Journey” features scenes from the couple’s trip.

“Gabby Petito, never goes outside,” she says while walking with Brian along a beach. The video, set to music, has nearly 450,000 views: Sunsets. Gabby driving the white van. Gabby running along the beach. Gabby preparing food. Other images show the couple sharing kisses, flipping backward on swings and cartwheeling on the beach.

“I love the van,” she says near the end of the video as the camera pans to the white Ford parked in the Utah desert.

The entry is the only one posted on their YouTube channel, Nomadic Statik.

“Thank you so much for watching, and we hope you tag along on our journey wherever the van takes us!” they wrote.

Yet there are signs something was seriously wrong.

Police in the southern Utah tourist town of Moab responded to a call about a possible domestic violence incident that officers say was more of a mental health crisis involving the couple on Aug. 12. The officers said in a police report no significant injuries were observed.

One witness called 911 and said he saw Laundrie and Petito fighting over a phone, according to the police report. When Laundrie got back into the van, Petito hit him in the arm before trying to climb through the driver’s side window.

Officers said they pulled the van over near the entrance to Arches National Park and saw Petito crying uncontrollably in the passenger seat. She told officers that she was struggling with her mental health.

“At no point in my investigation did Gabrielle stop crying, breathing heavily, or compose a sentence without needing to wipe away tears, wipe her nose, or rub her knees with her hands,” Officer Daniel Robbins said in his report.

Laundrie reportedly told Robbins that emotional tension had been building between him and Petito and that they were arguing more frequently because they had been traveling together for four to five months.

Laundrie said when the two of them began arguing in town, he had attempted to separate from Petito so they could calm down. Laundrie said he got into the van but Petito was afraid he would leave without her, so she went to slap him and he pushed her away to avoid the blow, according to the police report.

Officers recommended that the couple spend the night apart but didn’t file any charges after investigating.

It’s not clear what happened next.

Questions about what Grand Teton and Yellowstone National Park officials are doing with the case were forwarded to National Park Service headquarters in Washington, with spokeswoman Cynthia Hernandez saying in an emailed statement that the agency is coordinating with other law enforcement agencies about Petito’s whereabouts.

Petito is white, 5-foot-5 and about 110 pounds, with blond hair and blue eyes, police said. She has several tattoos including one on a forearm that reads, “let it be.”

Petito’s family members said in a statement that they need answers from Laundrie, including when he last saw her and “why he left Gabby all alone and drove her van to Florida.”

“These are critical questions that require immediate answers,” the statement said.