(CNN) -- He's known as "the millionaire with no face."
And South Korean officials apparently have questions for him.
Yoo Byung-un -- businessman, artist, ex-con and religious figure -- does not appear to have a direct financial stake in the Cheonghaejin Marine Co, which runs the ill-fated South Korean ferry Sewol.
But South Korean media have reported that some believe he controls the company through two of his sons, who own stakes in the firm through subsidiaries.
Yoo's allies strongly deny his involvement. A release issued Friday by a public relations agency representing Yoo insists that he doesn't have anything to do with any company tied to the ferry disaster.
Michael Ham, managing director of Ahae Press, said he knows Yoo "has been spending every single day of the past four to five years focusing on his photography work," not directing any firm tied to the sunken ferry.
"I am dismayed at the media reports linking him to the Sewol incident and suggesting that he is directly responsible for this tragedy," Ham said. "These claims cannot be further from the truth."
Authorities searched Yoo's home this week, plus offices of the company that owns the ferry, prosecutors told CNN. The Ahae Press release notes Yoo's sons are among dozens subject to travel bans in light of the ferry incident, calling this "blanket approach ... standard for investigations by Korean regulators."
Investigators have also searched 20 of the ferry owner's affiliates and a religious organization linked to Yoo, according to the semiofficial Yonhap News Agency.
The religious group and a private organization that conducts ship safety investigations are also facing probes in the disaster, Yonhap reported.
Prosecutors are looking for evidence of wrongdoing that might have contributed to the Sewol disaster.
How Yoo fits into that picture remains murky.
Little is officially known about Yoo, who earned his nickname as "the millionaire with no face" by making few public appearances.
He was convicted on fraud charges in the 1990s and spent four years in prison for tax evasion. He also headed a now-defunct ferry company that operated on the Han River.
Yoo is now believed to be involved with the Evangelical Baptist Church, a Korean religious group founded by his father-in-law. It now has 20,000 members, according to Yonhap.
More recently, he assumed a new identity of sorts as a photographer and artist who goes by the name "AHAE." The news release out Friday indicates his work has gone on display in the Louvre and the Palace of Versailles.
A biography on Ahae.com says he has an interest in organic farming and also describes him as an entrepreneur who once designed ships that traveled the Han River.
True to Yoo's nickname, Ahae doesn't show his face on the website. He only appears from behind, photographing nature scenes in his trademark style -- out an open window of his South Korean studio.
According the website bio, Ahae was born in 1941 in Japan, where his family was during Japanese colonial rule of Korea. That would make him 72 or 73.
The biography describes Ahae as "an inventor, entrepreneur, philanthropist, environmental activist, martial artist, painter, sculptor, poet, and photographer."
"Ahae has been a conservationist all his life and has done everything within his power to ensure that his business activities do not conflict with his endeavors to maintain the purity of the natural world," the biography reads. "His focus on organic products is a natural extension of his concern for the environment, and the individual in particular."
CNN's Michael Pearson reported and wrote from Atlanta; CNN's Kyung Lah reported from Jindo, South Korea. CNN's Steven Jiang and Greg Botelho contributed to this report.