SEOUL — Korean Air suspended the youngest daughter of its chairman, a sister of the infamous “nut rage” heiress, from her duties on Monday pending a police investigation of complaints she threw a cup of water at someone.

Cho Hyun-min, a senior vice president, faced pressure from the airline’s unions to step down after media reports she threw water into the face of an advertising agency manager, sparking a public backlash.

“Korean Air has excluded senior vice president Cho Hyun-min from work and suspended her from duties as of April 16 until the outcome of the police investigation,” the airline said in a statement.

Cho, also known as Emily Cho, apologized on Thursday for what she called her “foolish behavior”.

Korean Air said on Friday, in response to media reports Cho had thrown a water bottle at someone’s face, she had thrown either a water bottle or a cup on the floor, but not at anyone’s face. On Monday, the airline said it was a cup.

Cho, speaking to TV channel MBC after she cut short a vacation overseas and arrived in back home on Sunday, denied she had thrown a cup of water at the manager’s face but said she had “pushed” it.

She said her action was “foolish”.

It is the latest controversy to engulf the family that holds a big stake in South Korea’s largest airline group.

Cho’s elder sister Cho Hyun-ah, or Heather Cho, made headlines over a notorious “nut rage” incident in 2014, when she lost her temper over the way she was served nuts in first class before takeoff from New York.

Heather Cho demanded the flight crew chief be expelled from the plane after she was served macadamia nuts in a bag and not on a dish. The South Korea-bound plane had to return to the gate.

Cho was sentenced to a year in jail for violating airline safety laws, but was released after five months. She returned as an executive of Korean Air’s hotel affiliate in March.

Her younger sister’s tantrum has reignited public impatience with family-run conglomerates known as chaebol, over what some South Koreans see as unchecked bad behavior by the rich and powerful, especially second and third-generation children of the founders.

“Founders of conglomerates are considered myths, sacred. They have legitimacy, because they built the conglomerates from nothing,” said Chang Sea-jin, a business professor at Korea Advanced Institute of Science and Technology.

“But second-generation and third-generation leaders do not have such legitimacy. They are simply born with ‘golden spoons’ in their mouths,” he said.

Korean Air’s employee union and two pilots’ unions said on Sunday Cho Hyun-min’s action harmed the airline’s reputation and they wanted her to step down and offer a sincere apology to all of the company’s approximately 20,000 employees and the public.

“Why must our employees feel shame? Why must our employees, who have committed no crime, be the subject of criticism?” the unions said.

Cho apologized to employees in an email on Sunday. — Reuters