Investigators have confirmed the presence of bird feathers and blood in both engines of the Jeju Air jet that crashed last month in South Korea, killing 179 people, according to a source familiar with the ongoing probe.

After a deadly plane crash in South Korea, authorities are conducting a full investigation on 101 of the same model of aircraft that are operating in six local airlines.

South Korean investigators said Friday they expected to find more human remains as they began lifting the wreckage of the Jeju Air jet that crashed on landing last weekend killing all but two of the 181 passengers and crew aboard.

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. South Korean investigators previously said the flight data and cockpit voice recorders were key to finding out the cause of last month's crash that killed 179 people.

Muan international airport in South Korea, investigators have revealed the reason for the nation's worst aviation disaster. Reuters reported that blood and feathers were found in both the engines of the Jeju Air flight that allegedly led to the crash,