Kim Kyong Hui, Kim Jong Un’s aunt and wife of the recently executed Jang Song Thaek, has been in Switzerland since mid-December, the Japanese TV station TBS said on Wednesday, citing South Korean government sources.

Kim Kyong Hui, 67, flew to Switzerland on a special plane after Jang was publicly executed for treason on December 12, the station said.

More than one South Korean government officials said Kim Kyong Hui may be staying there for medical treatment for an unspecified disease and saw the possibility that her health is deteriorating, TBS reported.

Kim Kyong Hui, the younger sister of late North Korean leader Kim Jong Il, has long been seen as a guardian to Kim Jong Un, but has made no public appearances since September 2013, when North Korea celebrated the 65th anniversary of the nation’s foundation.

Speculation was rampant as to whether she would appear at a national memorial service for Kim Jong Il on December 17, but her attendance there was not confirmed. Since then, some South Korean media have speculated she might have already died of a heart attack or even suicide following the execution of her husband.

Kenji Fujimoto, a personal chef that served Kim Jong Il for 13 years, told NK News earlier this month that Kim Kyong Hui “was an alcoholic (and) her body was broken.”