Gabby Petito's boyfriend named person of interest after her disappearance during road trip

Police have named the boyfriend of Gabby Petito, a 22-year-old woman who went missing during a couple's cross-country road trip, a person of interest in her disappearance.

Brian Laundrie raised flags among Petito's family after he returned home to their home in North Port, Florida, with Petito's white Ford van -- but Petito was nowhere to be found.

The couple embarked on their trip in July from New York, where Petito is originally from, and made stops in Colorado and Utah, her family told ABC News. Her mother, Nichole Schmidt, last heard from her on Aug. 25, when Petito informed Schmidt that they were on their way to Grand Teton National Park and Yellowstone National Park in Wyoming. Laundrie returned to Florida on Sept. 1, police said.

The North Port Police Department in Florida announced Wednesday that Laundrie is now a person of interest in Petito's disappearance. The department has taken a lead in the investigation, since both parties reside there, but investigators "have no information" that a crime took place there, police said.

Petito's van was recovered from the North Port home where she resided with Laundrie and his parents, but investigators are not ready to release details from the search, North Port Police Public Information Officer Josh Taylor told reporters in a news conference Wednesday. A search warrant for the home has not been issued, Taylor added.

Laundrie has not made himself available to be interviewed by investigators, police said.

Investigators and Petito's family are pleading with Laundrie to share crucial information that could help locate her. North Port Police Chief Todd Garrison even accused Laundrie of "hindering this investigation," stating that "the answers will eventually come out."

"As a father, I can imagine the pain and suffering Gabby's family is going through," Garrison said in a statement. "We are pleading with anyone, including Brian, to share information with us on her whereabouts in the past few weeks."

Petito was last seen on Aug. 24 as she and Laundrie checked out of a hotel in Salt Lake City, her family said. Schmidt had received two text messages from Petito since Aug 25, but they did not contain any photos or updates on the couple's plans, so it is not clear whether Petito actually sent those texts. Schmidt also posted her last Instagram post, which was not geotagged, on Aug. 25.

Petito seemed "excited" the last time Schmidt spoke to her, but she began to worry after she had not heard from her for several days, she said.

"A few days is one thing when you’re out camping, but when it starts to become seven, eight, nine, 10 days, that’s a problem," Schmidt told ABC News.

Instagram posts from both Petito and Laundrie show them at the Mystic Hot Springs in Utah on July 26 and on a large rock structure at Arches National Park in Grand County, Utah, on Aug. 12.

On Aug. 12, police in Moab, Utah, responded to an "incident involving Brian Laundrie and Gabrielle Petito," but there "insufficient evidence existed to justify criminal charges," Moab, Utah Police Chief Bret Edge said in a statement Tuesday night.

Officers responded to a report of a domestic problem after a witness said the couple, involved in an altercation at the Arches National Park, drove off in a white van, according to a police report.

When police officers located a van and pulled it over for a traffic stop, the couple admitted to arguing and that Petito had slapped Laundrie, according to the report. The couple also stated to police that Laundrie did not hit Petito.

Petito told police that she suffers from severe anxiety and other medical conditions, which were redacted from the police report, and that the arguments had been building for the past few days. Police labeled the incident as a "mental/emotional break" rather than a domestic assault, according to the report.

On Aug. 19, Petito posted an eight-minute compilation of the couple's adventures so far on her YouTube channel "Nomadic Statik." Her family reported her missing to the Suffolk County Police Department in New York on Saturday.

Taylor, of the North Port Police Department, expressed concern that Laundrie had been in Florida for 10 days without saying anything before Petito's family reported her missing.

"We're hopeful to talk to him. He needs to talk to us," Taylor said. "We need to know exactly where he was, where she was, their last locations. And the fact that he was back here for 10 days, you know the family reported her missing 10 days later ..."

While Laundrie has not spoken publicly, his family released a statement Tuesday through their attorney Steven P. Bertolino, describing Petito's disappearance as "an extremely difficult time" for both families.

"This is understandably an extremely difficult time for both the Petito family and the Laundrie family," the statement read. "It is our understanding that a search has been organized for Miss Petito in or near Grand Teton National Park in Wyoming. On behalf of the Laundrie family, it is our hope that the search for Miss Petito is successful and that Miss Petito is re-united with her family. On the advice of counsel, the Laundrie family is remaining in the background at this juncture and will have no further comment."

Petito's family released a statement Tuesday claiming that "the one person that can help find Gabby refuses to help," adding that they "beg the Laundrie family to not 'remain in the background' but to help find who Brian referred to as the love of his life."

"Brian is refusing to tell Gabby’s family where he last saw her," the Petito family said. "Brian is also refusing to explain why he left Gabby all alone and drove her van to Florida. These are critical questions that require immediate answers."

The FBI and agencies in Utah and New York are also participating in the investigation.

ABC News' Alexandra Faul contributed to this report.