The Vegas authorities have reopened the case and are following up on information that has surfaced.
The Juventus forward has strenuously denied accusations made by Kathryn Mayorga that she was raped by him in a Las Vegas hotel room in 2009.
On Thursday, Portugal coach Fernando Santos said Ronaldo also will not be called up for the next round of worldwide games in November.
"My clear conscious [sic] will thereby allow me to await with tranquillity the results of any and all investigations".
Mayorga's lawsuit, however, said she had named the footballer to police "within weeks of the initial report".More news: Boris Johnson turns up heat on PM at Conservative meeting
Ronaldo had also missed Portugal's first two post-World Cup matches last month, with Santos saying then that Ronaldo had only just moved to Italian club Juventus and was still settling down there.
The 33-year-old superstar reportedly met with Portugal coach Fernando Santos and Portuguese federation president Fernando Gomes and collectively agreed it was best for Ronaldo to step away for a few games.
Larissa Drohobyczer, one of Mayorga's lawyers, told reporters that whistle-blowing website Football Leaks had provided documents that showed correspondence between Ronaldo and his team of fixers around the time of the incident, which they are considering making public.
"The #MeToo movement was very important to Kathryn and her decision to consult with us and to go forward in this case", Stovall said.
Mayorga was not at the conference and her lawyers claimed the alleged assault had caused her severe mental and emotional damage.