Investigators searching for Gabby Petito believe her fiancé and those around him are withholding critical information related to her disappearance and are refusing to come forward, police said Thursday night.
"I believe Brian has the information," said Police Chief Todd Garrison of North Port, Florida, referring to the fiancé, Brian Laundrie.
"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," he said.
Petito, 22, was traveling with Laundrie in her white 2012 Ford Transit van with a Florida license plate, police said. When her family didn't hear from her since late August, they reported her missing on September 11. Police believe she was in the Grand Teton National Park in Wyoming before the last communication with her family, who lives in New York.
"We are conducting a missing person investigation. Two people went on a trip, and one person returned. And that person is Brian. And we're looking for Gabby, and he is not willing to provide us any information," Garrison told CNN's Don Lemon on Thursday night.
According to a timeline of events provided Friday by Petito family attorney Richard Stafford, Gabby FaceTimed with her mother on August 24, saying she was leaving Utah and headed to the Tetons.
Gabby and her mother exchanged multiple texts the next day, at which point her family believes she was in the Tetons. Gabby and her mother texted again on August 27.
The last text her family received from Gabby was August 30, per the timeline, but they doubt she was the author of the text message. Stafford has previously declined to share what the message said or why the family did not believe it was her writing.
On September 11, police found the van the couple was traveling in at the home Petito shared with Laundrie and his parents in North Port, Florida. Laundrie allegedly returned to North Port on September 1, police said in a news release.
Laundrie's sister, Cassie Laundrie, told ABC's "Good Morning America" in an interview that aired Friday, "Me and my family want Gabby to be found safe. She's like a sister and my children love her."
"All I want is for her to come home safe and sound and this to be just a big misunderstanding," Cassie Laundrie said, adding she hasn't been able to speak with her brother since he returned home.
The FBI's office in Denver on Thursday announced it was joining the investigation into Petito's disappearance.
"No piece of information is too small or inconsequential to help in law enforcement's efforts to bring Ms. Petito home," the office said on Twitter, calling on the public to submit any information to the FBI, including "potential sightings, photos, videos, or any other details."
'Do the right thing,' Petito's stepfather says
Cassie Laundrie said she had spoken with police, but Josh Taylor, a spokesperson for the North Port Police Department told CNN, "That was news to me," adding he can't confirm that she spoke with North Port police.
"She may have spoken to police, but I would not consider the family being entirely cooperative," Taylor said. "This started Saturday with us showing up to the door and we were essentially handed a piece of paper with their attorney's contact information. That has been the extent of our conversation with Brian's parents. We have never spoken a word with Brian."
Authorities are investigating some materials they found in the van after they processed it, though they didn't clarify what exactly they're looking into, Taylor said in a prior news briefing.
And the Laundries haven't been talking to Petito's family, who have been pleading people to come forward.
'Right now, we don't have a crime,' police say
Garrison told CNN his department isn't working to obtain a search warrant for Laundrie's home because they haven't concluded that a crime has occurred. "In order to get a search warrant, you have to be tied to a crime. Right now, we don't have a crime," Garrison said.
He added Laundrie has invoked his Fifth Amendment right, which generally means a person cannot be forced to make statements he or she feels might be negative or used against them. The amendment is usually invoked so a person can avoid answering specific questions. The right must be affirmatively waived.
"So I can't compel him to speak," Garrison said. "All of our information has been directed through an attorney. That can change. The attorney can come forward and say, 'listen, Brian wants to provide a statement now.'"