International soccer star Cristiano Ronaldo won't face criminal charges in connection with a decade-old rape allegation against him, Las Vegas prosecutors announced Monday.

Clark County District Attorney Steve Wolfson said in a statement to NBC News that he determined the sexual assault claim can't be proven beyond a reasonable doubt and no charge will be filed after a new police investigation was conducted.

Ronaldo, 34, was accused in a September 2018 civil lawsuit, seen by NBC News, of sexually assaulting a Nevada woman in his Las Vegas hotel penthouse in 2009. His accuser, Kathryn Mayorga, claimed in the suit that she spoke to police in 2009 and underwent a medical examination after the alleged rape, but that Ronaldo's representatives asked for private mediation.

Mayorga claimed in the lawsuit that the soccer star and his "team" pushed Mayorga into signing a nondisclosure agreement while she was still suffering from severe trauma from the alleged attack.

She is now publicly accusing Ronaldo and suing for damages resulting from battery, intentional infliction of emotional distress and coercion, according to the lawsuit.

Ronaldo denied Mayorga's allegations in a statement on Twitter in October last year.

"I firmly deny the accusations being issued against me," the tweet read. "Rape is an abominable crime that goes against everything that I am and believe in. Keen as I may be to clear my name, I refuse to feed the media spectacle created by people seeking to promote themselves at my expense."

Attorneys for Mayorga did not immediately respond to a request for comment from NBC News.

Although he no longer faces criminal charges in the Las Vegas case, the civil lawsuit is still pending. Attorneys for Ronaldo filed paperwork in June, seen by NBC News, asking permission to begin the process of dismissing the suit.

Representatives for Ronaldo did not immediately respond to a request for comment from NBC News.