(NEXSTAR) – Missing 22-year-old Gabrielle “Gabby” Petito, whose body was believed to have been recovered over the weekend at a Wyoming national park, sent a final text message to her mother that raised red flags, according to a newly unsealed police warrant.

Petito’s mother received an “odd” text on Aug. 27 that read, “Can you help Stan, I just keep getting his voicemails and missed calls,” according to the North Port, Florida, police warrant. “Stan” refers to Petito’s grandfather, but her mother, Nicole Schmidt, told police that Gabby never referred to him by his first name.

“The mother was concerned that something was wrong with her daughter” after getting the message, according to the warrant.

That message was the last one that Petito would send. Petito, who was traveling cross-country with boyfriend Brian Laundrie while recording their trip on a YouTube vlog called “VAN LIFE,” also abruptly stopped posting on social media.

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Investigators say that Petito sent multiple text messages and talked with her mother many times during the course of the trip, which they started in July. As the weeks passed, the conversations appeared to show “more and more tension between her and Laundrie.”

The search warrant was signed to allow North Port Police Department investigators access to the contents of an external hard drive found in Petito’s white van.

On Monday, police and FBI agents converged on the North Port home where 23-year-old Brian Laundrie, who investigators are currently looking for, lives with his parents. Laundrie returned alone to his parents’ home with the white van that the couple was using.

The FBI declined to say what they learned Monday, citing an ongoing investigation, but could be seen removing a Ford Mustang from the address.

The FBI announced over the weekend that a body believed to be Petito was found near the east border of Grand Teton National Park, but full forensic identification hasn’t been released pending an autopsy scheduled for Tuesday.