Florida Police are searching a wildlife reserve Saturday for 23-year-old Brian Laundrie, a person of interest in the disappearance of his girlfriend, Gabrielle "Gabby" Petito. The couple traveled across country during the summer, with Petito's family not hearing from her since late August.

Laundrie and Petito, 22, left in July on a cross-country trek in a converted van to visit national parks across the western states. Police said Laundrie was alone when he drove the van back to his parents' home in North Port, Florida, on September 1.

Investigators said they believe he is on the Carlton Reserve in the Sarasota, Florida area of the Gulf Coast. More than 50 North Port police officers, FBI agents and members of other law enforcement agencies searched the 24,000-acre reserve, reported CTV News.

"His family says they believe he entered the area earlier this week," North Port Police tweeted Saturday.

The Laundries told officers they hadn't seen him since Tuesday, who latter requested a meeting with FBI investigators to discuss his disappearance.

Authorities are questioning how Laundrie got to the reserve, as his vehicle was found back at his family's home, not at the reserve. Family members told investigators he took his car.

Attorneys for the Petito family released a statement claiming Laundrie was not "missing."

"All of Gabby's family want the world to know that Brian is not missing, he is hiding. Gabby is missing," read the statement from the law firm of Richard B. Stafford.

Earlier in the week, Petito's family pleaded for the Laundrie family to tell them where their son last saw her. Petito and Laundrie were childhood sweethearts who met while growing up on Long Island, New York. His parents later moved to North Port, about 35 miles south of Sarasota.

Earlier, the North Port Police said in a statement they understood the frustration over the lack of progress in finding Petito. Her family filed a missing persons report September 11.

"We are frustrated too," the statement read. "For six days, the North Port Police Department and the FBI have been pleading with the family to contact investigators regarding Brian's fiance, Gabby Petito. Friday is the first time they have spoken to investigators in detail."

Laundrie has been identified as a person of interest in the "multiple missing person" case.

"It is important to note that while Brian is a person of interest in Gabby's disappearance, he is not wanted for a crime," read the statement.

The couple's trek began in July from Long Island, and were to reach Oregon around the end of October according to their Instagram. However, Petito vanished after her last known contact with family in late August from Grand Teton National Park in Wyoming, reported the authorities.

The FBI in Denver said agents conducted ground surveys in Wyoming, with help from the National Park Service and local law enforcement agencies to find clues concerning Petito's disappearance. Her family last made contact with her at the national park.

Investigators in Florida were hopeful Laundrie was somewhere in the wildlife reserve near Sarasota.

Police spokesperson Josh Taylor said depending on his skills, he could survive out in the reserve for some time. He added: "Certainly, we prepare for all different possibilities, but you know, our goal is to locate him and bring him back to North Port."