ALBUQUERQUE, N.M. – UPS confirmed the identity of the pilots on board UPS Flight 2976 that crashed in Louisville Tuesday. UPS says Captain Richard Wartenberg, First Officer Lee Truitt, and International Relief Officer Captain Dana Diamond were operating the flight.

An investigation has been launched into the cause of the deadly Tuesday crash, which occurred as a McDonnell Douglas MD-11 was taking off.

Nine people remain missing after a UPS plane departing Louisville Muhammad Ali International Airport in Kentucky on Tuesday crashed, killing at least 12 people.

Captain Richard Wartenberg, First Officer Lee Truitt and International Relief Officer Captain Dana Diamond were those on board the flight, according to UPS. Friday, a family shared that two of its members, Louisnes Fedon and his young granddaughter Kimberly, were also among those who died after the plane went down.

Dozens of federal aviation investigators are on the ground in Louisville searching the crash site's debris field, which covers nearly a half-mile area.

The UPS cargo plane crew tried to control the aircraft for about 25 seconds before it crashed into a ball of flames shortly after taking off on Tuesday.

The cockpit voice recorder captured a persistent bell that began about 37 seconds after the crew called for takeoff thrust, and the bell continued until the recording ended, an NTSB official said.