A Chinese citizen journalist, Chen Qiushi, who covered Wuhan’s initial outbreak of the Chinese coronavirus in late January 2020 resurfaced in a YouTube video on Thursday after a 600-day absence from the public, the Wall Street Journal reported on Friday.

“Mr. Chen re-emerged Thursday with a short appearance on a friend’s live video feed on YouTube and a letter posted to his account on Twitter,” according to the Journal.

“Over the past year and eight months, I have experienced a lot of things. Some of it can be talked about, some of it can’t,” Chen’s letter read. “I believe you understand.”

A mixed martial artist friend of Chen’s named Xu Xiaodong hosted the September 30 YouTube video in which Chen made his first appearance since the start of the pandemic.

“Chen said little about his disappearance, instead extolling the physical and mental health benefits of mixed martial arts,” the Journal observed.

“In his first Twitter post after his re-emergence, Mr. Chen advertised a new registered account on Douyin, the Chinese version of TikTok, saying he planned to organize a charity martial-arts competition,” the newspaper detailed.

Chen posted a statement to Twitter just one hour later, however, revealing that “the Douyin account is now blocked.”

The BBC identified Chen as a “former human rights lawyer turned video journalist” while reporting on his whereabouts in September 2020. At the time, Chen’s martial artist friend, Xu, had uploaded a video to YouTube in which he alleged that Chen was in a “safe place.”

“Qiushi [Chen] is still under the supervision of a certain agency and hasn’t come home yet,” Xu said in the video.

Chen is a registered resident of Qingdao, an eastern Chinese port city. Qingdao is located roughly 660 miles northeast of the central Chinese city of Wuhan, which was the epicenter of China’s first Chinese coronavirus outbreak in late 2019. Chen traveled from Qingdao to Wuhan in January 2020 to act as a citizen journalist and report on the city’s then-emerging epidemic.

Chen distributed his citizen journalism in Wuhan via short videos shared through his social media accounts and via YouTube. According to the Journal, Chen’s videos were viewed “millions of times on the popular WeChat social media platform before his account was taken down. Later, he continued to post videos on YouTube, which is blocked in China.”

From January to February 2020, Chen documented Wuhan’s unfolding outbreak by interviewing people who had lost relatives to the virus and filming inside local state hospitals, according to the Journal.

“In one video, he talked to another citizen journalist who had been visited by local police,” the newspaper recalled, revealing how Chinese authorities attempted to censor coverage of Wuhan’s outbreak early on.

“On 7 February a video was shared on his Twitter account featuring his mother, who said he had gone missing the day before,” the BBC recalled last September.

“Mr Xu later alleged in a YouTube video that Mr Chen had been forcibly quarantined,” according to the broadcaster.