Investigators searching for wreckage from last week’s deadly midair collision between a US military Black Hawk helicopter and an American Airlines plane near Washington, DC, conducted an overnight scan of the Potomac River where the aircraft fell using advanced imaging technology to map the riverbed and locate debris.

Salvage crews have been working to recover the wreckage of the American Airlines jet and the Black Hawk helicopter.

Wreckage of the military helicopter involved in a mid-air collision with an American Airlines passenger jet that killed all 67 people on both aircraft was recovered from the Potomac River, federal officials said.

NTSB will examine the debris and recording devices to figure out what went wrong.

The mangled remains of the Black Hawk helicopter involved in last week’s deadly midair plane crash in DC were pulled out of the Potomac River Thursday, the National Transportation Safety Board announced.