The black boxes of a Boeing jetliner that crashed in South Korea last month stopped recording about four minutes before the accident, South Korean officials said Saturday, possibly complicating investigations into the cause of the disaster that killed 179 people.

Solving the mystery behind December's Jeju Air disaster becomes more difficult, with authorities revealing the black boxes failed to record the aircraft’s final four minutes.

The two flight recorders on board a South Korean airliner stopped working before the jet crashed during an emergency landing and subsequent crash that killed 179 of the 181 people on board, officials said Saturday.

The last four minutes of data before the disaster which killed 179 people are missing, transport authorities say.

Authorities have said black boxes holding the flight data and cockpit voice recorders stopped recording around four minutes before the crash.

The flight data and cockpit voice recorders on the Jeju Air jet that crashed on Dec. 29 stopped recording about four minutes before the airliner hit a concrete structure at South Korea’s Muan airport,