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 two black boxes on the Boeing jet involved in the worst aviation disaster on South Korean soil stopped recording about four minutes before the accident, the transport ministry said on Saturday. So

The missing data deepens the puzzle of what caused the deadly air disaster in Muan, South Korea, late last month.