(CNN)The family of Brian Laundrie, the fiancé of 22-year-old Gabby Petito -- who was reported missing by her family nearly a week ago -- told police in North Port, Florida, they haven't seen him since Tuesday, according to police spokesperson Josh Taylor.
"We've been trying all week to talk to his family, to talk to Brian, and now they've called us here on Friday, we've gone to the home, and they're saying now they have not seen their son," Taylor told CNN's Chris Cuomo on Friday night. "So we are working through those details as we speak. It is another twist in this story."
The disappearance of the fiancé was confirmed by the Laundrie family lawyer.
In a statement Friday night to CNN, attorney Steven Bertolino said Brian Laundrie's whereabout "are currently unknown."
He added: "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."
The FBI declined to comment on this statement when asked for verification by CNN.
Separately, North Port Police Chief Todd Garrison wrote on Twitter on Friday night the conversation between the Laundrie family and police was complete. The chief also asked for calm, adding, "Please let us work through this and information will be forthcoming."
Police previously had visited the home but the family refused to talk and instead gave authorities the information for their attorney, Taylor said earlier this week. Petito's family and their attorneys have pleaded with the Laundrie family for several days to speak to authorities and help them find the young woman.
The FBI has now also released a new Missing Person poster, asking for help in the search for the young woman.
'Two people went on a trip, and one person returned'
On Thursday, Garrison said he believed the family was withholding critical information.
"I believe Brian has the information," the police chief told CNN's Don Lemon. "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 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 said Thursday.
Authorities believe Laundrie was the last person to see Petito before she went missing.
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. 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.
"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 Taylor, the police spokesperson, previously 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 for people to come forward.
"We've had no communication between our family and theirs. It's absolutely absurd. We don't understand why," Petito's stepfather, James Schmidt, told CNN affiliate Court TV.
Schmidt explained that he is in Jackson, Wyoming, as a liaison between his family and law enforcement as investigators search for Petito. He said he believes Laundrie knows information about his stepdaughter's disappearance and is "hiding behind" his attorney.
"He grew up with Gabby; they went to school together. They're not strangers. They've known each other for a long time," Schmidt said.
Schmidt addressed Laundrie during the interview, calling on him to come forward with information he may know.
"This is the love of your life. It's been out there on social media. You posted on your accounts. If that is true, then do the right thing. You need to do it now. Stop waiting," Schmidt said.
'Right now, we don't have a crime,' police say
Garrison told CNN on Thursday that his department wasn'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.'"
The couple did, however, have a recent interaction with police in Moab, Utah.
Last month, officers with the Moab City Police Department responded to reports of disorderly conduct involving Petito and Laundrie, which ended with a report describing them as having "engaged in some sort of altercation."
The report released by the police department indicates Laundrie and Petito had a physical fight following an argument, but "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 the report from Officer Eric Pratt.
The officers who responded to the incident suggested that Laundrie and Petito should separate for the night, according to the report. Petito is described by one officer as "confused and emotional."
"After evaluating the totality of the circumstances, I do not believe the situation escalated to the level of a domestic assault as much as that of a mental health crisis," Officer Daniel Robbins wrote in the police report.
No charges were filed. Robbins wrote Laundrie said the pair had been traveling together for "the last 4 or 5 months."
