The FBI on Friday  launched an investigation into the disappearance of Brian Laundrie, who is considered a “person of interest” in the mysterious disappearance of his fiancée, Gabby Petito.

Petito, a 22-year-old lifestyle influencer, vanished last month near the end of a “van life” cross-country road trip that she and Laundrie, 23, had been writing about on Instagram since July 2.

Petito’s parents haven’t heard from her since late August as she headed to a  hike in Wyoming’s Grand Teton National Park with Laundrie. 

Laundrie returned home without Petito Sept. 1 to North Port, Florida, where he lives with his parents and Petito. Police found the white van the couple had been driving at the home. 

Laundrie  offered no explanation for Pepito’s disappearance, and refused to talk to police. Now he has also vanished. Laundrie’s parents suddenly told police Friday that they haven’t seen their son since Tuesday.

“Be advised that the whereabouts of Brian Laundrie are currently unknown,” Steven Bertolino, an attorney for the family, told ABC Friday. “The FBI is currently at the Laundrie residence removing property to assist in locating Brian. As of now the FBI is now looking for both Gabby and Brian.”

North Port police spokesman Josh Taylor told CNN Friday: “We’ve been trying all week to talk to his family, to talk to Brian, and now … they’re saying they have not seen their son. So we are working through those details … It is another twist in this story.”

North Port Police Chief Todd Garrison said in a tweet Friday that the “conversation at the Laundrie home is complete,” and a statement would be forthcoming. He asked for “calm.”

Garrison said on CNN Thursday that he believed Laundrie’s parents were withholding  important information.

“I believe Brian has the information,” said  police chief. “I believe people around Brian may also have the information, and we are pleading to those people to come forward. Provide us the information that we need to find Gabby and reunite Gabby with her family because she deserves it and her family deserves it.”

Petito’s parents, who live in New York, reported her missing on Sept. 11. “We haven’t been able to sleep or eat, and our lives are falling apart,” Petito’s parents and step-parents wrote Thursday in a letter to Laundrie’s family asking for help.

Police named Laundrie a person of interest in the case on Wednesday and said he was the last person known to have seen Petito.

Utah’s Moab City Police Department released disturbing body camera footage of a response on Aug. 12 to a call about domestic violence concerning the couple.

Police can be seen attempting to calm a distraught Petito, who tells officers she has been struggling with her mental health and with her boyfriend while living in the van’s close quarters. Petito says in the footage that Laundrie locked her out of the van, and police can be seen questioning her about slapping Laundrie.

Despite the fraught situation, “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,” according to a report from Moab Police Officer Eric Pratt.