NORTH PORT, Fla. – A search warrant shed new light on the investigation into Gabby Petito’s disappearance and death Monday, as FBI agents zeroed in on the home of Brian Laundrie’s parents.

FBI agents spent hours inside the North Port, Florida home, leaving with boxes of property and a mustang in the driveway. The same mustang that parents told police Laundrie drove to an environmental park on Tuesday when he left his home.

“They’re still building their case and that’s very obvious,” said Greg Skordas, a defense attorney and former prosecutor who is not affiliated with the case.

“They’re going to go through that with a fine-toothed comb and look for anything that would corroborate what they found when they found her. For example, if they found dirt or rocks or twigs or something that’s consistent with a certain part of the country, a certain part of Wyoming.”

Authorities found what’s believed to be Gabby Petito’s body more than 2,000 miles away in Wyoming and more than three weeks after she was reportedly last seen or heard from. But Petito’s parents worry the last message they received from her phone wasn’t really her.

A search warrant to get into a computer hard drive was released Monday and is shedding new light on the timeline surrounding Petito’s disappearance. According to the warrant, the couple left New York mid-June this year for a vacation to Utah, traveling to national parks along the way. Petito “had many talks with her mother” on her phone and “during these conversations there appeared to be more and more tension between her and Laundrie.”

Then on August 27, her mom received an “odd text” from her daughter.

According to the search warrant, “The text message read, ‘Can you help Stan, I just keep getting his voicemails and missed calls.’ The reference to ‘Stan,’ was regarding her grandfather, but per the mother, she never calls him ‘Stan.’”

That was her last communication with anyone, according to the warrant. Her cell phone “was no longer operational” and she stopped documenting the trip on social media. The family told investigators, “This was not normal behavior…and they became worried about her.”

“Search warrants are granted for investigations, and they’re based on a level of what we call ‘probable cause,’” Skordas said. “In other words, law enforcement felt that there was probable cause that a crime had been committed and there may be some evidence of that crime inside that house. That’s a little different than the evidence you would need to convict someone in front of a jury. That’s a much, much higher standard.”

Brian returned to Florida with Petito’s van but without her on September 1. The warrant notes he entered the city just before 10:30 a.m.

On September 11, Petito’s family reported her missing from their home in New York. On that same day her van was found at the Laundrie’s address where Petito also lived in North Port, Florida. The Laundrie family said she wasn’t at their home and they didn’t know where she was.

Laundrie wouldn’t speak with law enforcement on the advice of his attorney. And according to the warrant, his parents refused to let him speak to them either.

“He’s following the instructions of his attorney not to speak with law enforcement and that’s acceptable. That’s certainly allowed under the constitution,” Skordas said. “The fact that he hasn’t cooperated isn’t as much of a problem I think as he has now fled and disappeared, and nobody seems to know where he is.”

Regarding Laundrie’s parents, Skordas said, “If [police] believe that his parents or his family have hidden evidence, hidden him, obstructed justice in some way, they too could be charged.”

On September 14, police served a search warrant on Petito’s van and found a hard drive that “may contain viable digital forensic data that could assist in location of said missing.”

Investigators would later learn from Laundrie’s parents that Brian left that same day with a backpack. His parents told police he went to an environmental park and that he hasn’t been seen or heard from since. Crews searched a wildlife reserve over the weekend and found nothing.

“The police I think have acted pretty appropriately,” Skordas said.

“I know a lot of people are frustrated and feel like they should have put the clamps on [Laundrie] earlier but really it was a missing person’s case. She’s an adult. She had had some communication with her parents after allegedly they were in Wyoming and so I think police were being cautious.”