Human remains were found in a Florida nature reserve on Wednesday near the spot where authorities ramped up a manhunt for 23-year-old Brian Laundrie more than four weeks after his missing fiancée, Gabby Petito, was found dead in a Wyoming national park.

Officials could not immediately confirm that the remains were those of Laundrie.

The Sarasota County medical examiner’s office responded to the scene after some of Laundrie’s personal items were found nearby ― by his own parents.

The items, including a backpack and notebook, were found in an area that had until recently been underwater, said Michael McPherson, FBI special agent in charge of the Tampa division.

McPherson said the FBI was “using all available forensic resources to process the area,” but that the task would likely take the team “several days.”

He added: “I know you have a lot of questions, but we don’t have all the answers yet. We are working diligently to get those answers for you.”

An attorney for Chris and Roberta Laundrie said earlier Wednesday that the pair informed law enforcement Tuesday evening that they were going to the Myakkahatchee Creek Environmental Park to search for their son early Wednesday, and promptly found some evidence he had been there, sparking a larger law enforcement response.

The swampy park is located north of Chris and Roberta Laundrie’s Florida home. It also connects to the nearby Carlton Reserve, another site that attracted law enforcement attention during the manhunt.

The FBI’s Tampa bureau confirmed Wednesday afternoon that “items of interest” were found in the area in connection with the case.

Brian Laundrie had been named a person of interest in Petito’s disappearance after he returned home on Sept. 1 from a monthslong cross-country road trip through the American West that he and Petito had taken together. He returned in the same van the couple had left in ― alone.

The Laundrie family hired an attorney soon thereafter. Brian refused to cooperate with the search for Petito, and was believed to be holed up at his parents’ Florida home until mid-September, when the family attorney announced that Brian had also vanished.

A warrant for Laundrie’s arrest was later issued for his alleged use of a bank card belonging to his fiancée.

Authorities located Petito’s body on Sept. 19 along the eastern border of Grand Teton National Park, which was the last place the 22-year-old had been seen alive. The FBI ruled her death a homicide, and a coroner later determined she was strangled.

On Sept. 20, the FBI raided the Laundrie family home, removed boxes of evidence and spoke at length to Roberta and Chris, who have steadfastly declined to speak with the media directly. Petito’s family members say they have also not been able to question the Laundries.