The bodies of the people killed in the DC aircraft crash last week are still being looked for.

An Army helicopter carrying three soldiers and a 64-person American Airlines plane collided on Wednesday, January 29.The two planes crashed into the Potomac River, and rescuers are still working to recover the dead.

As of this writing, 55 of the 67 fatalities had been recovered from the water.The rescue crews are reportedly working in “tough” circumstances.

“There’s ice in the river, it’s particularly cold and that makes it very challenging to [rescue] crews,” international maritime search and rescue & emergency response expert Matthew Schanck told BBC News. Continue reading below.