The Wall Street Journal reports that authorities issued the warrant to see if Ronaldo's DNA matches "that found on the dress of a woman who has accused him of rape."
Mayorga went to police the day after the alleged attack on June 12, 2009, where she did not refer to Ronaldo by name but described him as an athlete and public figure.
But the WSJ claims that the dress Mayorga wore that night in 2009 remains critical in the investigation. This is because a law-enforcement official says DNA other than Mayorga's was found on the dress. Las Vegas police want to know whether Ronaldo's DNA sample matches what was found on Mayorga's dress.
Ronaldo's lawyer has confirmed that authorities want his DNA, and has said it is just a "standard request."
Peter S. Christiansen, Ronaldo's lawyer, said: "Mr. Ronaldo has always maintained, as he does today, that what occurred in 2009 in Las Vegas was consensual in nature, so it is not surprising that DNA would be present, nor that the police would make this very standard request as part of their investigation."
The warrant has been served in Italy, where Ronaldo is currently a striker for the reigning Serie A champion Juventus FC.
Ronaldo "firmly" denied the allegations in a series of tweets last October.
"I firmly deny the accusations being issued against me," he said, "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."
In a second tweet, he added : "My clear conscious will thereby allow me to await with tranquillity the results of any and all investigations."
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