Brazil international Dani Alves was formally accused of sexual assault at a nightclub in Barcelona last week, a Catalan police source confirmed to the news agency EFE.
A spokesman for the local police in Barcelona told ESPN a complaint was filed on Monday relating to an incident at Sutton, a popular night spot in the city, but could not confirm the identities of those implicated.
"The investigation is still ongoing," the spokesman said.
ESPN has also contacted Alves' camp for comment. He denied involvement while speaking on the Spanish TV show, Y Ahora Sonsoles, saying: "I would like to deny everything, first. I was there, in that location, with more people, having a good time. Everybody knows that I love to dance. Having a good time, but without invading the space of others
"I'm very sorry, but I don't know who that young lady is, I don't know who she is, I've never seen her in my life"
EFE reported that a woman has filed a police report against Alves, alleging that he touched her inappropriately under her clothes without consent during a night out on Dec. 30.
After the incident, the woman says she told security what had happened and local police were informed and took witness statements.
Alves, 39, was in Barcelona following his participation at the World Cup with Brazil in Qatar. He had spent time in the city training with Barca's B team in the lead-up to the finals and returned following the Selecao's elimination..
He is now back in Mexico, where he plays for Pumas UNAM following a 22-year professional career that has seen him play for Bahia, Sevilla, Barcelona, Juventus, Paris Saint-Germain and Sao Paulo.