SEOUL: A Korean Air heiress known for a “nut rage” tantrum that sparked national uproar was summoned for questioning Thursday for illegally hiring immigrants to work as maids, the latest scandal to engulf her billionaire family. Cho Hyun-ah kept her head bowed as she reported to immigration authorities in Seoul on Thursday. “I’m sorry to cause trouble,” she said in a quiet voice before entering the office. She faces allegations that she illegally hired some 10 Filipinos to work as housemaids in the family home by disguising them as company trainees to obtain visas. It is against the law in South Korea to hire foreigners as domestic helpers. A series of scandals have left Korean Air chairman Cho Yang-ho and his family facing mounting scrutiny over a spate of alleged wrongdoings that have riled the public and even sparked protests by the firm’s employees. The family first shot to international infamy in 2014 when Cho Hyun-ah forced two Korean Air flight attendants to kneel and beg for forgiveness after she was served macadamia nuts in a bag rather than a bowl. She ordered the Seoul-bound flight back to the gate so one of them could be ejected in an incident quickly dubbed “nut rage” that many South Koreans felt typified the way ultra-wealthy families often behave. She was sentenced to a year in prison by a lower court. But after serving five months in jail she was was freed when the appeals court cleared her of hampering an air route — the most serious charge — as the aircraft was still on the ground. Her younger sister Cho Hyun-min recently won unflattering headlines with her own tantrum when she allegedly splashed fruit juice over a business associate in a fit of rage. Prosecutors stopped short of bringing charges against her after the victim reconciled with her. But the incident set off a flurry of new allegations about the family’s other alleged wrongdoings. Among the allegations authorities are now investigating include smuggling of furniture and food, tax evasion, hiring of illegals and verbal abuse and assaults against employees. Korean Air workers launched an online chat room detailing various grievances they had with the family. On Friday some employees will hold their fourth weekly rally calling for Cho family to take a back seat in the company. Police have also summoned the chairman Cho’s wife Lee Myung-hee for questioning on Monday after more than ten people claimed they had been physically or verbally assaulted by her. Lee is also suspected of involvement in the illegal hiring of foreign maids and will be questioned in this case as well, the immigration office said.