Brazilian football great Ronaldinho and his brother spent a second consecutive night in a Paraguayan prison on Saturday after a judge dismissed their request for house arrest.
Ronaldinho, 39, and Roberto Assis, 49, were detained late on Wednesday for allegedly entering Paraguay with fake passports.
After more than 24 hours under police guard at a luxury hotel in Asuncion, the brothers were taken into custody on Friday and spent the night in a police cell with one other inmate.
At a court hearing on Saturday, for which the brothers arrived handcuffed, judge Clara Ruiz Diaz ordered the pair to remain in jail pending the police investigation, citing a flight risk.
Ruiz Diaz described the alleged crime as a "serious one against the interests of the Paraguayan state", according to local media.
Tarek Tuma, one of Ronaldinho's lawyers, said an appeal would be lodged in the coming days.
"He [Ronaldinho] doesn't understand what's going on," Tuma told reporters.
Ronaldinho and Assis travelled to Paraguay to participate in a children's charity event and promote a new book. They have denied any wrongdoing and said they were presented with the passports as a "gift" upon arriving at Asuncion's international airport on Wednesday morning.
In November 2018, the brothers had their passports seized by Brazilian police after failing to pay a fine resulting from a 2015 court case.
They recovered the passports last September -- effectively ending a 10-month foreign travel ban -- upon paying a million-dollar fine for building a fishing platform without environmental permits.
Ronaldinho retired from football in 2018 after a career that included a World Cup triumph in 2002 and two FIFA World Player of the Year awards.