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.

All of the plane and chopper wreckage has been fished from the icy Potomac River, as the National Transportation Safety Board continues to investigate the Jan. 29 mid-air crash that killed 67 people.