Chang Song-min, a former aide to South Korea’s late president Kim Dae-jung, wrote on social media last week that Kim is “comatose,” according to The Korea Herald. Chang claimed he has secured the information from an unidentified source in China.

“I assess him to be in a coma, but his life has not ended,” Chang wrote. His claims came as Kim’s younger sister and trusted aide Kim Yo Jong was reportedly handed a raft of new responsibilities, including overseeing Pyongyang’s ties with South Korea and the U.S.

Kim Yo Jong has previously been touted as a potential successor to her brother, and in recent years has quickly risen up the North Korean hierarchy to a position of significant power.

Rumors of Kim’s demise are relatively common, and in April an extended absence prompted speculation that he had died or slipped into a coma following a medical procedure. He re-appeared in public after around three weeks, with South Korea’s spy agency suggesting he had been sheltering from the COVID-19 coronavirus pandemic.

Since that absence, the North has released multiple photos and videos of the young leader. South Korean intelligence later said there was no indication that Kim was ill or had undergone surgery.

But Chang claimed that all recent photographs had been faked and that Kim Yo Jong is being pushed forward to take over from her incapacitated brother, if only temporarily.

“A complete succession structure has not been formed, so Kim Yo Jong is being brought to the fore as the vacuum cannot be maintained for a prolonged period,” Chang said, according to The Korea Herald.

There is no other evidence that Kim is in a coma. Little reliable information comes from inside North Korea, making it difficult for even South Korean and U.S. intelligence agencies to build up an accurate picture of Pyongyang’s internal political events. This makes the North fertile ground for rumors and misinformation.

North Korean experts on social media gave Chang’s claims short thrift. John Delury, a professor at Yonsei University in Seoul, South Korea, tweeted that North Korean experts were discussing “how silly this all is.”

Harry Kazianis, the senior director of Korean studies at the Center for the National Interest, dismissed the reports, noting Chang’s dubious sourcing. “Can’t we stop falling for this garbage?” he tweeted.