A police helicopter crashed Wednesday night, killing two people aboard, as authorities responded to an "active shooter," incident, authorities said.

As Arizona continues to remember the Department of Public Safety troopers lost in last week’s helicopter crash, investigators are now working to determine exactly what went wrong.

From a police shooting in a northern Arizona neighborhood that led to a tragedy involving an Arizona Department of Public Safety helicopter to the latest on the search for the mother of "Today" show host Savannah Guthrie,

Three people were rescued by helicopter after falling through ice in Queens on Friday.

Ranger 56 had undergone an inspection just days before the helicopter's crash Wednesday night in Flagstaff, according to the Arizona Department of Public Safety.

The low-altitude flights are happening through Wednesday, and they are being done to measure expected background radiation ahead of the Super Bowl, the National Nuclear Security Administration said.