The FBI and Department of Homeland Security said on Saturday that ongoing investigations around reported drone sightings over New Jersey have found many reports are, in fact, manned aircraft.

For weeks, New Jersey residents have spotted mysterious drones in the night sky throughout the state. Some New Yorkers and Pennsylvanians have seen them, too. These sightings have confounded local and federal authorities, who have been unable to determine the drones’ origins or their purpose. Here’s what we know about the ongoing mystery.