There was no distress call from the Virginia State Police helicopter that crashed in a wooded area outside of Charlottesville, Virginia Saturday after documenting the violent demonstrations and protests in the city. Killed in the accident were the pilot, 48-year-old Lt. H. Jay Cullen, a veteran Virginia State Police trooper with nearly 20 years of flight experience and 41-year-old Trooper Berke M. M. Bates, who was training to be a pilot.

The National Transportation Safety Board (NTSB), which is investigating the incident, said the flight crew was conducting a continuous video feed of activities on the ground until the helicopter was diverted to provide support for a motorcade carrying Virginia Governor Terry McAuliffe.

The helicopter went down about seven miles southwest of the Charlottesville airport, with the aft portion of the tail boom became lodged in a tree.

No "black box"

Circumstances surrounding the crash and subsequent fire remain a mystery. Cullen did not issue a distress call. The NTSB will not be able to glean information from a a flight data recorder or a cockpit voice recorder. The helicopter was not equipped with those devices, nor was it required to be.

Investigators for the NTSB and Virginia State Police are interviewing witnesses who reported seeing the helicopter in flight shortly before the crash. They are also working with local authorities to recover the helicopter wreckage to a secure location where additional examination and documentation can be conducted.

The entire investigation is expected to last 12-18 months.