Federal and state agents have been at the American Flight Academy (AFA) all day Wednesday removing boxes of documents.
Sources tell NBC Connecticut Troubleshooters that investigators are zeroing in on a maintenance hangar at AFA at the Brainard Airport in Hartford.
Agents have been hauling nearly 12 boxes of documents from inside the flight school's offices to several law enforcement vehicles, according to NBC Connecticut Troubleshooters on the scene.
State police confirm they are assisting the U.S. Department of Transportation's Inspector General Office.
AFA is owned by Arian Prevalla, the survivor of a deadly plane crash back in October, that killed his student Feras Freitekh. Prevalla said he fought and struggled with Freitekh before the crash. Officials called the crash intentional early on in the investigation.
On Wednesday, the National Transportation Safety Board spokesman said their final report of the deadly student crash was referred to the FBI.
Four incidents involving AFA have been reported since last October— including two deadly crashes, an emergency landing and a small crash with no injuries.
NBC Connecticut reached out to Prevalla's attorney.