Embattled Japanese casino mogul Kazuo Okada is ‘unfit’ to the director of a public company and Universal Entertainment Corp. president Jun Fujimoto vows to back up his allegations.

A supposed private letter of Fujimoto dated June 21 made rounds ahead of the scheduled annual meeting of Universal shareholders on Thursday. Reuters, which saw the letter, reported that this was the first time Fujimoto shared his thoughts on Okada’s predicament since the latter was removed from his post in a rare Japanese boardroom coup.

Fujimoto minced no words as he called out Okada’s purported illegal dealings, saying that he had evidence to prove his allegations. The Universal Exec, however, did not say what that evidence was

“I think Chairman Okada is unfit to be in management of a public company,” Fujimoto said in the letter, which was written in Japanese. “I’m confident that I can prove that with irrefutable physical evidence.”