Brian Laundrie, 23, has not been charged with a crime, but he is now considered a person of interest in the case, according to police in his hometown of North Port, Florida. North Port police told Fox News Tuesday they want to speak with him about the case.
"Where is she? Please tell her family," reads one comment with more than 1,700 likes on Laundrie's last photo posted to Instagram.
A number of photos posted to his account have been flooded with similar comments demanding answers from Laundrie on his fiancé's disappearance.
The couple was traveling cross-country in their Ford Transit van and sharing photos and videos of their trip to social media. The 22-year-old Petito's mother reported her missing on Sept. 11, but they had last spoken in the final week of August.
Laundrie's last photo posted on Aug. 13 has a long-winded caption about primates and concludes with, "I think if we all want breathable air and drinkable water we all need to learn how to live with less."
Petito was last seen at Grand Teton National Park in Wyoming, and she posted pictures taken in Arches National Park, just north of Moab, Utah, on Aug. 12.
Police on Wednesday said Laundrie returned home to Florida as early as Sept. 1 in the couple's van — 10 days before Petito's family reported her missing. On Sept. 11, authorities recovered the van that the couple was traveling in as part of their investigation. The investigation involves law enforcement agencies in multiple states and the FBI, the latter of which began a forensic examination on the vehicle Tuesday, North Port police told Fox News.
A search is underway in Wyoming. The missing woman's family says he refused to tell them where he last saw her.
"Everyday the search for Gabby continues the Schmidt and Petito family becomes more desperate," Richard Stafford, the lawyer representing the Petito's mother, Nicole Schmidt. "They are frantically searching for answers and information in their daughter’s disappearance while Brian sits in the comfort of his home."
Stafford continued: "Brian claims he wants to sit in the background while we search for Gabby in the wilderness of the Grand Teton and Yellowstone national parks. Brian left Gabby in the wilderness with grizzly bears and wolves while he sits in the comfort of his home. In his home! Brian, how could you do this to Gabby? You selfishly remain silent while Gabby is all alone in the wilderness. Brian, your silence is reprehensible! We beg you to do the right thing and help us bing Gabby home."
Police seized the van Monday as part of their investigation, which involves law enforcement agencies in multiple states and the FBI, the latter of which began a forensic examination on the vehicle Tuesday, North Port police told Fox News.
Fox News' Michael Ruiz contributed to this report.