CHICAGO (NewsNation Now) — Just days ago, officers were seen in tactical gear with assault rifles at the Carlton Reserve in Venice, Florida in search of Brian Laundrie. But Tuesday, parts of the reserve were opened back up to the public.

Chris Swecker, a former assistant director of the FBI Criminal Investigation Unit, says there’s a lot that can be learned about the Gabby Petito case from past high-profile cases — specifically as it relates to possible sightings of Laundrie.

“Not to make light of this, but people are still calling in and saying they see D.B. Cooper and Jimmy Hoffa — even Elvis. So … there has to be a lot of organization around this,” Swecker said.

New surveillance video shows an individual on a bicycle in the Florida reserve where authorities have been seeking Laundrie for weeks. Some have speculated that it is Brian Laundrie.

“You have to have a national agency like the FBI or the U.S. Marshals or a federal agency to handle this because the sightings are all over the place,” Swecker said. “They’re on the Appalachian Trail, I’ve heard of sightings in the Bahamas, in Mexico. This is extremely resource-intensive. And you have to think long and hard before you put it out there to the public to call in on these leads.”

Gabby Petito vanished while on a cross-country road trip with Laundrie in a converted camper van. The trip was well-documented on social media until it abruptly ceased, allegedly somewhere in Wyoming.

Petito, 22, was reported missing Sept. 11 by her parents after she did not respond to calls and texts for several days. Petito’s body was found Sept. 19 just outside Grand Teton National Park in Wyoming. A Teton County coroner said last week that Petito died by strangulation three to four weeks before her body was found.

Laundrie has not been charged in Petito’s death, but authorities say he is a person of interest in the case.