Dive team brought in to find Brian Laundrie at the Carlton Reserve in Florida

A law enforcement underwater dive team joined the effort at the Carlton Reserve in Florida on Wednesday.

A large van and boat from the Sarasota County Sheriff’s Office arrived midday Wednesday at the reserve, a swampy 25,000-acre reserve in Venice, Florida, where Laundrie told his parents he was headed last week.

The dive team, called the Sheriff’s Underwater Recovery Force (SURF), is made up of “highly trained underwater specialists” who are “called upon to search for evidence of crimes and victims of drowning, water accidents and foul play,” the sheriff’s department website says.

North Port police said the arrival of the dive team “does not mean anything has been found. It’s a part of the overall search process.”

The team, made up of about 10 divers, was requested by North Port police on Wednesday morning, said Sarasota County Sheriff’s office spokesperson Kaitlyn Perez.

“These divers are specifically trained and very talented in low visibility bodies of water,” Perez said. “They dive down where you and I can’t see anything at all. They utilize technology and other special equipment to help them get down deep into really deep bodies of water, so they’re out there right now to recover whatever it is that they might find.”

The fourth day of searching the reserve ended Wednesday evening, according to officials.

“Nothing found. We will be back out Thursday, similar operation,” North Port police tweeted.

The ongoing search comes as investigators try to piece together what happened to Petito, 22, and Laundrie, 23, on their road trip in a white Ford Transit van through the American West this summer.

Petito’s remains were recovered in Wyoming’s Bridger-Teton National Forest.

Throughout the trip, the couple had posted online regularly about their travels with the hashtag #VanLife, but those posts abruptly stopped in late August. Laundrie and the van — but not Petito — went to his parents’ home in North Port, Florida, on Sept. 1. Her family, unable to get in touch with her, reported her missing 10 days later.

Laundrie’s parents then reported him missing on Sept. 17, saying he had left home three days earlier to go to the reserve and hadn’t returned.

The FBI said the bureau would like information from anyone who may have had contact with Petito or Laundrie, anyone who visited the Spread Creek Dispersed Camping Area in the Bridger-Teton National Forest between Aug. 27-30 or anyone who may have seen their vehicle.

In the days since she was reported missing, Petito’s story has become a national obsession for many, spurring digital detectives to comb through the couple’s online trail to try to solve the case. The story has also further highlighted the tens of thousands of missing persons stories that do not garner such intense interest among the public.

Given the national attention on the case, several people have come forward to say they interacted with the couple in late August. And evidence from a 911 call about a “domestic dispute” involving Petito and Laundrie shows the couple’s volatile relationship was not as aspirational as their sun-drenched lives on Instagram and YouTube suggested.