SEOUL (THE KOREA HERALD/ASIA NEWS NETWORK) - Cho Hyun Min, a former senior vice-president of South Korea's flag carrier Korean Air Lines, returned home after 15 hours of police questioning during which she reportedly denied allegations of assaulting an employee of an advertising agency in March.

Cho was called in on Tuesday (May 1) on charges including business obstruction and assault.

Cho reportedly told police that she threw an empty glass cup towards a wall, not at the person, because she felt that she was being ignored during their conversation about a Korean Air advertisement filmed in England.

On the allegation that she threw a cup of plum juice at other advertising agency employees who were also at the meeting, Cho said that she had not intended to throw the cup of juice when she pushed the cup, but its contents had accidentally splashed onto the people around her, police said.

Cho's alleged assault has escalated into a major scandal involving South Korea's largest air carrier. The scandal was sparked by an anonymous post accusing the heiress of throwing a tantrum.

Other cases of whistleblowing have since taken place, with growing criticism of members of the owner family of the company, who are also accused of dodging taxes by bringing in luxury items aboard their company flights.

Her elder sister Cho Hyun Ah, also a former vice-president at Korean Air, was known for the infamous "nut rage" incident in 2014, where she forced a South Korea-bound flight back to the boarding gate at a New York airport because she was angry about the way her macadamia nuts were served - in a bag, not on a plate.

Their father, Hanjin Group chairman Cho Yang Ho, had sent out a public apology last week and fired his two daughters from their executive positions.

He vowed to bring in professional business operators, but public ire and criticisms have continued.

Hanjin Group is the parent company of Korean Air Lines.

Police said they will continue to analyse Cho's phone records, recorded voice clips and witness's testimonies to clarify what exactly happened during the meeting.

Meanwhile, some Korean Air employees said on Wednesday that they would begin collective action against Mr Cho by staging a candlelight protest on Friday (May 4) to pressure the Hanjin Group chairman to step down.

During the protest, employees will hold placards that read "Cho Yang Ho Out" and stage satirical performances, such as throwing a can of plum juice and macadamia nuts, two items allegedly used during tirades by the Cho daughters.