Gabby Petito's mother said the final text she received from her daughter's phone was 'odd' and concerning, according to search warrant

• A search warrant showed the last text Gabby Petito's mother received from her was on August 27.
• In the message, Petito referred to her grandpa by his first name, which concerned her mother.
• Authorities are still searching for Brian Laundrie, who has been missing since Tuesday.

The final text Gabby Petito's mother, Nichole Schmidt, received from her daughter's phone before the 22-year-old went missing was "odd," and it left Schmidt feeling "concerned," said a Florida search warrant for a hard drive belonging to Brian Laundrie, Petito's fiancé.

The search warrant, which Insider reviewed, was signed by a Florida judge on Friday, the same day Laundrie, a person of interest in Petito's missing-person case went missing himself, and two days before authorities announced that they had found a body near Grand Teton National Park that could be Petito's remains.

Petito disappeared during a cross-country road trip with Laundrie, and she was reported missing on September 11 by her mother after she hadn't heard from Petito since late August.

The discovery of the body and an impending Tuesday autopsy may begin to provide answers in the case, which has captivated the nation.

The final text message Schmidt received from Petito's phone arrived on August 27, the search warrant said.

The text said, "Can you help Stan, I just keep getting his voicemails and missed calls."

The warrant said Stan is the name of Petito's grandfather, but Schmidt told authorities that her daughter never called him "Stan." The message left Schmidt concerned that something had happened to her daughter, the warrant said.

The message is the last known communication anyone had with Petito, and following the exchange, her cellphone ceased being operational, and the young van-life influencer stopped posting on social media, the warrant said. Petito's family said that was abnormal behavior, and that they became even more concerned about her well-being.

Petito's cellphone had been turned off for about 15 days as of Friday, the warrant said.

While executing a search warrant of the couple's van on September 14, authorities discovered an external hard drive potentially belonging to Laundrie. The warrant said that law enforcement believed the drive held information that could aid in solving the case. Friday's warrant was issued to search the drive.

The warrant also showed that during the couple's monthslong road trip, Petito had "many talks" with her mother that suggested that tension between Petito and Laundrie was escalating.