LAS VEGAS (AP) — Wynn Resorts Ltd. said Monday that Nevada gaming officials have ended their investigation into allegations by a Japanese billionaire that the casino operator made an improper donation to the University of Macau and found no evidence of wrongdoing.

In addition, Wynn said that a federal court in Nevada granted its motion to dismiss a shareholder complaint against the company related to the donation, saying that there wasn't a legal basis for the case to go on.

The accusations stem from an ongoing battle between former friends and business partners Kazuo Okada and company CEO Steve Wynn.

Okada used to be Wynn Resorts' single largest shareholder but the company tried to forcibly buy back his shares after it said it found that Okada made improper payments to overseas gambling regulators. The two have traded accusations of unethical or illegal conduct during the extended legal, and seemingly personal, dispute.

Wynn is seeking to remove Okada from its board at a special shareholder meeting set for Feb. 22. Okada has filed suit in a Nevada federal court to halt the meeting, saying that the proxy calling for it makes false statements.

Wynn said its board has already deemed Okada unsuitable. It said a lengthy investigation by former FBI Director Louis Freeh uncovered evidence of improper conduct in connection with Okada dealings with Philippine officials.

On Monday, Wynn said that Institutional Shareholder Services Inc., a major proxy advisory firm, issued a report recommending that shareholders vote to remove Okada.

Wynn shares fell 11 cents to $126.26 in morning trading.