In December, some families of some people were killed in a plane crash on Jeju Island and have filed criminal lawsuits against 15 people, including the South Korean transport minister and the airline's CEO to achieve professional negligence.

Relatives of 72 relatives called for a more thorough investigation of the crash, which caused 179 of 181 people, making it the deadliest plane crash on South Korea's soil.

They claimed that the crash was “not a simple accident” but “a major civil disaster caused by negligence in managing preventable risks.”

For nearly five months, authorities are still studying what caused the plane to crash at Muan International Airport and then exploded.

Police have launched a criminal investigation ahead of this latest complaint and have banned Jeju Air CEO Kim E-Bae from leaving the country, but no one has been prosecuted.

A relative, Kim Da-Hye, condemned the "lack of progress" in the investigation.

"We are full of anger and despair. After taking extraordinary measures to file criminal proceedings, we will not give up and will continue to pursue the truth," Mr. Kim said in a statement to the media.

Among the 15 nominated in the complaint are government officials, airline officials and airport staff responsible for construction, supervision, facility management and bird control.

The complaint filed Tuesday raised questions about the crash, including whether air traffic control responded appropriately and whether mound reinforcement at the end of the runway violated regulations.

The plane, a Boeing 737-800, took off from Bangkok, the capital of Thailand on the morning of December 29 and flew to Moon, South Korea.

After five minutes of contact with MUAN International Airport, the pilot reported hitting a bird and announcing a Mayday signal.

The pilot then attempted to land in the opposite direction, during which time no landing gear was deployed on the abdomen of the aircraft. It later covered the runway, slammed into a concrete structure and exploded.

Earlier this year, investigators said they found bird feathers in both engines of the jet, but did not conclude that the degree to which the bird strike was a contributing factor.

Since the incident, some family members’ families have also been targeted by online conspiracy and malicious jokes.

These include suggestions that families are “excited” about the authorities getting compensation, or that they are “fake victims.” As of March this year, eight people were arrested for posting derogatory and slanderous online posts.