An American Airlines plane with 64 people on board collided with an Army helicopter over Washington, D.C., and crashed into the Potomac River.

Forty-one sets of remains have been recovered and 28 of those victims have been positively identified, Washington, D.C., Fire and EMS Chief John Donnelly Sr. said at a news conference Friday. Next of kin notifications had been made to 18 families as of 6 a.m. Friday, he said.