The black boxes of the American Airlines plane submerged in the Potomac River from Wednesday’s crash with a military helicopter have been recovered, the National Transportation Safety Board said late Thursday.

Investigators have recovered the flight recorders—also known as black boxes—from both the commercial jet and the military helicopter involved in the mid-air collision near Reagan National Airport in Washington,

Police boats combed the banks of the Potomac River on Friday, moving slowly under rainy skies and scanning the shoreline as investigators sought clues into the midair collision that killed 67 people and raised