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NORTH PORT, Fla. (WFLA) — The last communication 22-year-old Gabby Petito had with her family before her mysterious disappearance left her mother concerned that something was wrong, according to a search warrant obtained by 8 On Your Side.

The warrant allowed detectives to analyze an external hard drive that was found in Petito’s white van she had been traveling in with her fiancé, 23-year-old Brian Laundrie, on a cross-country trip. Police say Laundrie returned home to North Port alone with the van the morning of Sept. 1.

Petito was reported missing on Sept. 11 by concerned family members who said they hadn’t heard from her since the end of August.

According to the search warrant, the “last communication anyone had” with Petito was Aug. 27 when her mother, Nichole Schmidt, said she received an “odd text” from her daughter.

“Can you help Stan, I just keep getting his voicemails and missed calls,” the text read, according to the search warrant.

The warrant explains that “Stan” references Petito’s grandfather. However, Schmidt said Petito never called her grandfather “Stan.” The text left Schmidt “concerned that something was wrong with her daughter,” according to the search warrant.

The warrant, dated Sept. 15, goes on to say that Petito’s cell phone “has been turned off for approximately 15 days.” It also noted that Petito had been in communication with her mom throughout the trip and had conversations where “there appeared to be more and more tension between her and Laundrie.”

The search warrant makes no mention of an Aug. 30 text that Schmidt previously spoke about in a news conference she held after Petito was officially reported missing

“The last text I got from her was on Aug. 30,” Schmidt said at the time. “I don’t know if that was her texting me or not.”

Last week, Schmidt described how her “mother instinct went off” the day she reported her daughter missing.

Investigators are still trying to piece together what led up to Petito’s disappearance. An autopsy is set to begin Tuesday on human remains found in Wyoming on Sunday that FBI agents say match the 22-year-old’s description.

Meanwhile, in North Port, law enforcement agencies are continuing their search for Laundrie, who was reported missing by his family last week. Laundrie, identified as a person of interest in the Petito case, had retained a lawyer and was not cooperating with the investigation, according to police.

FBI agents spent several hours at the Laundrie home on Monday serving a search warrant connected to the Petito investigation.