NORTH PORT, Fla. (WFLA) — North Port police officers and FBI agents searched the Carlton Reserve Saturday to find Brian Laundrie, fiancé of missing North Port woman Gabby Petito.

The North Port Police Department tweeted that Laundrie’s family believes he went to the reserve earlier in the week. His family previously said he was last seen Tuesday while wearing a hiking bag with a waist strap.

North Port police spokesperson Josh Taylor said this is being investigated as a missing person case since there still is no crime for officers to investigate.

“We can’t just go just pulling people in,” Taylor said. “He certainly has the Fifth Amendment (right) not to speak.

The initial search focused on the 200 acres at the Myakkahatchee Creek Environmental Park, where Taylor said Laundrie is believed to have entered the reserve. The search then expanded into the Carlton Reserve, which encompasses 25,000 acres.

Taylor said 50 officers from five different local agencies had joined the search for Laundrie. So far, vehicles, K9s, air units, and drones were deployed in what is being called a grid search.

Police say evidence bags containing Laundrie’s clothes were used for the K9s in the search. They were taken Friday while officers were at the Laundrie home.

“We’re hopeful that he’s out here,” Taylor said. “Certainly, we prepare for all different possibilities, but you know, our goal is to locate him and bring him back to North Port.”

Taylor said Laundrie could be out in the nature preserve for months if he wanted, depending on his skills.

Law enforcement called off the search later in the evening “due to darkness” but will pick back up Sunday morning.