By CBSMiami.com Team

SARASOTA (CBSMiami/CNN) – The FBI has confirmed the body found in Grand Teton National Park is Gabby Petito.

In a release, the FBI said the “initial determination for the manner of death is homicide.”

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Authorities are still searching for Brian Laundrie, Petito’s missing fiancé.

Police are combing the Carlton Reserve, 25,000 acres of terrain which includes prairies and wetlands.

North Port police posted photos and video of their search on social media.

“Terrain’s very difficult. Essentially, 75% of it is underwater, and other areas that are dry, we’re trying to clear. So we’re expecting to get wet by the end of the day, and check the entire area for Brian Laundrie,” said North Port Police Commander Joe Fussell, who is heading up the search.

Petito, 22, and Laundrie, 23, had been road tripping in a white van through the American West over the summer. Laundrie and Petito had been living with his parents at the North Port home before the road trip. Laundrie returned to the home on September 1 in their van, but without Petito.

Her family reported Petito missing on September 11.

On Monday, the FBI spent hours and removed items in their search of the Laundrie home. A Ford Mustang convertible was also towed away.

Laundrie’s parents, Christopher and Roberta, were escorted from their home so agents could execute a search warrant. They were later brought back inside for questioning.

His parents had previously told police that they had not seen Laundrie since last Tuesday, which launched a search that initially centered on a nearby nature reserve.

An attorney for Laundrie’s family, Steven P. Bertolino, said he would also hold a press conference Tuesday, but later canceled the event. He said the FBI requested he not hold the conference.

A search warrant claims ‘more and more tension’ between the couple

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Investigators have obtained a search warrant for an external hard drive found in the van last week.

Petito sent multiple text messages and had many talks with her mother via cellphone, according to the stated probable cause for the search warrant. And during those conversations, there “appeared to be more and more tension between her and Laundrie,” it says.

On August 27, Petito’s mother received one last communication from her daughter, which she called an “odd text,” the probable cause affidavit says.

The message read: “Can you help Stan, I just keep getting his voicemails and missed calls.” Because the text message referred to Petito’s grandfather as Stan, her mother was concerned that something was wrong, the warrant states.

Following that text message, Petito’s phone was no longer operational and she stopped posting anything on social media about their trip, the warrant says

One more text came on August 30 that read, “No service in Yosemite,” but her family doubts she wrote it, Richard Stafford, an attorney representing Joseph Petito, and her mother Nicole Schmidt said.

There has been other evidence of tension between the two.

CNN obtained a 911 audio recording from the Grand County Sheriff’s Office in Moab, Utah, in which a caller reports what he called a “domestic dispute” between a couple.

The caller described a man slapping a woman and continuing to hit her until they got into their car and drove off in a white van with a Florida license plate, according to the audio.

Police later stopped the couple.

Although Petito and Laundrie are described in a police report as getting into a physical fight following an argument, “both the male and female reported they are in love and engaged to be married and desperately didn’t wish to see anyone charged with a crime,” Officer Eric Pratt wrote in the report.

At the suggestion by police, the couple separated for the night, the report said, which described Petito as “confused and emotional.”

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CBSMiami.com Team