Human remains found in a Florida wildlife area on Wednesday belonged to a man who had been declared a “person of interest” in the murder of his fiancée, the F.B.I. said on Thursday, ending a search that had drawn intense national interest.
A comparison of dental records confirmed that the remains, which were found in the Carlton Reserve and the adjoining Myakkahatchee Creek Environmental Park in Sarasota County, were those of Brian Laundrie, the F.B.I. said.
The discovery of the remains came seven weeks after Mr. Laundrie returned home from a monthslong van trip without his fiancée, Gabrielle Petito, and about four weeks after she was found dead in a national forest in Wyoming.
Yet the authorities and Ms. Petito’s family members were still grasping for answers about what happened during and after the couple’s cross-country road trip, which Ms. Petito, 22, and Mr. Laundrie, 23, chronicled at length on social media.
Michael F. McPherson, the special agent in charge of the F.B.I.’s Tampa field office, said on Wednesday that the authorities had found a notebook and a backpack that belonged to Mr. Laundrie near the remains in the Myakkahatchee Park, a heavily wooded, 160-acre park in North Port, Fla.
The park connects to the Carlton Reserve, a 24,565-acre wildlife refuge, where the authorities had been searching for Mr. Laundrie for weeks. The items were found in an area that until recently had been underwater, Mr. McPherson said.
“I know you have a lot of questions, but we don’t have all the answers yet,” Mr. McPherson said at a news conference on Wednesday, at which he did not take questions. “We are working diligently to get those answers for you.”
The identification of Mr. Laundrie’s remains came after Ms. Petito’s body was found in September in the Bridger-Teton National Forest, by Grand Teton National Park in Wyoming.
A coroner determined that the manner of Ms. Petito’s death was homicide, and that the cause was strangulation. The coroner, Dr. Brent Blue of Teton County, Wyo., said her body had been outside for three to four weeks before it was found on Sept. 19.
Mr. Laundrie’s items and his remains were found after his parents, Chris and Roberta Laundrie, had informed the F.B.I. and the police on Tuesday evening that they intended to come to the park on Wednesday morning to search for their son, the family’s lawyer, Steven Bertolino, said in a statement.
After a brief search off a trail that Mr. Laundrie frequented, the family and law enforcement officials found “some articles” belonging to him, Mr. Bertolino said. The discovery prompted a “more thorough investigation of that area” by law enforcement agencies.
“Chris and Roberta Laundrie have been informed that the remains found yesterday in the reserve are indeed Brian’s,” Mr. Bertolino said in a statement on Thursday. “We have no further comment at this time and we ask that you respect the Laundries’ privacy at this time.”
Richard Stafford, a lawyer for the Petito family, said the family had no immediate comment.
“They are grieving the loss of their beautiful daughter,” Mr. Stafford said on Thursday. “Gabby’s family will make a statement at the appropriate time and when they are emotionally ready.”
Ms. Petito left with Mr. Laundrie from New York in July in a white Ford van outfitted with a bed and other necessities for visiting national parks and nomadic travels that they called “Van Life.”
On Sept. 1, Mr. Laundrie returned to the home in North Port, Fla., where he and Ms. Petito had been living. He drove there, alone, in the van, which had been registered to Ms. Petito.
Ten days later, Ms. Petito’s family reported her missing. The search for her soon involved the F.B.I. and National Park rangers and stretched across at least two states. Through a lawyer, Mr. Laundrie had declined to speak to investigators, according to the police, who described him as a “person of interest” and not as a suspect.
Then, six days after Ms. Petito was reported missing, Mr. Laundrie’s parents told the police that they had not seen him for several days, starting a second search for a missing person. The authorities began to scour the Carlton Reserve, and the F.B.I. served a search warrant at the Laundrie residence.
The Search for Gabby Petito
On Sept. 11, the family of Gabrielle Petito reported her missing. She seemed to have disappeared during a cross-country trip with her fiancé, Brian Laundrie. Her remains were found in Wyoming on Sept. 19.
A federal arrest warrant was later unsealed for Mr. Laundrie in Wyoming, charging him with debit card fraud after the authorities said he had unlawfully used a Capital One bank debit card in late August. The authorities did not say whether the debit card belonged to Ms. Petito.
As Ms. Petito’s family and the police pleaded for help from the public, the case drew widespread attention on social media, including from some who scrutinized the couple’s cheerful Instagram posts and others who criticized the lack of similar attention to the cases of missing women of color.
On Aug. 12, the police in Moab, Utah, responded to a report of a “domestic problem” between the couple, according to a police report. It said that Mr. Laundrie and Ms. Petito had “some sort of argument.”
The report said that he told her to take a walk and calm down, and that Mr. Laundrie and Ms. Petito both told the officers that they were in love, engaged to be married and “desperately didn’t wish to see anyone charged with a crime,” the report said.
Mr. Laundrie told one officer that “issues between the two had been building over the last few days,” it said.
Body camera footage shows that, during the encounter, Ms. Petito cried and said she suffered from anxiety. In the police report, Ms. Petito is recorded as saying she moved to slap Mr. Laundrie because she feared that he “was going to leave her in Moab without a ride.”
Both told the police that the episode should be classified as a “mental/emotional health ‘break’” and not as domestic assault, the report said.
The police described Mr. Laundrie in the report as the victim of the incident. They arranged for him to stay in a hotel that night while Ms. Petito kept the van. No charges were filed, the report said.
Alan Yuhas contributed reporting.