The prosecution said Wednesday that Korean Air heiress Cho Hyun-ah was suspected of having interfered with a government investigation into an incident she was involved in on a flight last month.

The eldest daughter of the airline owner Cho Yang-ho was arrested on Dec. 30 on charges of changing flight plans, violence and obstruction of crew duty.

While indicting Cho Wednesday, the Seoul Western District Prosecutors’ Office filed the additional charge that she had interfered in the Transport Ministry’s probe by having company officials attempt to cover up the case and manipulate evidence.

The prosecution also indicted a Korean Air executive, surnamed Yeo, on charges of destroying evidence and forcing crewmembers involved to give false testimony to minimize the impact of the case. 

A Transport Ministry official, surnamed Kim, was also charged with leaking information on the investigation to the airline.

Kim, a former Korean Air employee for 15 years, phoned Yeo about 30 times and exchanged 10 text messages between Dec. 7 and the day before the ministry’s probe was launched, according to the prosecution.

Yeo and Kim were both arrested late last month along with Cho.

The prosecution said it would launch an additional investigation into the Transport Ministry over suspicions that public servants had received special favors from Korean Air. Some ranking officials were accused of having their seats upgraded regularly for free.

The ministry began to investigate the “nut rage” incident on Dec. 8 ahead of the prosecution’s probe as the public criticism escalated.

Public anger grew over the ministry’s investigation after the deplaned cabin crew member claimed in a media interview that the probe had proceeded unfairly. He said that officials from the airline had been present during the probe, and that he had been ordered to revise his written testimony more than 10 times.

Facing public doubts over the suspicious relationship between the ministry and the company, the ministry conducted an internal inquiry into its own probe and admitted that the investigation process had not been conducted impartially.

The case has gained keen international attention with critics at home and abroad arguing that the incident was an epitome of social injustice. The case has also shed light on those on the receiving end of anger from those in high authority, raising public calls for a change in the rigid, hierarchical corporate culture.

By Lee Hyun-jeong (rene@heraldcorp.com)