Authorities were continuing their search Monday for Griffin Prince, 13, who has been missing since a June 18 boat crash.

The wreck in the area of Shoal Creek near Buford Dam killed Griffin’s 9-year-old brother, Jake.

Monday morning, the FBI joined local and state authorities in the search for Prince’s body in the depths of Lake Lanier, according to Sgt. Stephen Wilbanks, Hall County Sheriff’s Office spokesman.

The FBI dive team, based out of Quantico, Va., has equipment that allows divers to stay below the surface longer than some local dive team equipment. They join 10 Hall County divers.

“The FBI is often requested by other local, state or even other federal agencies to provide services, expertise or specialized equipment,” said Special Agent Stephen Emmett, spokesman for the FBI. “That is what has happened here.”

The team also brought more sonar equipment and remote-operated vessels.

“It just ensures that we’re even that much more thorough in our search area,” Wilbanks said. “It allows a much closer inspection of these areas, an added layer of assurance that we’re exhausting all possible resources.”

Wilbanks said officials expanded the search area, which is estimated at about one square mile.

“We’ve expanded the search area just a little bit, but we’re also going back over some of those previous search areas with the FBI’s equipment and looking at those targets again for some closer inspection,” Wilbanks said.

The Georgia Emergency Management Agency has provided the search teams with two cadaver dogs, trained to pick up odors emanating from the lake.

Forsyth County has portable Geographic Information System mapping on site, giving the search teams a clear overview of what areas have been searched and which areas still need to be searched.

Over the weekend, search crews used sonar and a remote-operated vessel. No divers were used because of the weekend boat traffic.

Wilbanks did not give a timeline for the search, but said with the new manpower and equipment, it could be extended if needed.

“With the new capabilities we have on hand, with the other equipment and resources, it allows us to reassess everything and extend (the search) out a little further if we need to,” he said.

Emmett said the FBI will be on site for the week and “will then re-evaluate thereafter.”

Some areas of the lake reach depths of more than 100 feet, and Wilbanks said at about 50 to 60 feet below the surface visibility becomes “near zero.”

Water temperatures at that depth are in the upper 40s.

Low visibility, coupled with brush and timber at the bottom of the lake, makes diving difficult.