RIO DE JANEIRO – A Brazilian judge on Monday ordered the arrest of a man suspected of being involved in an alleged plot to place explosives at a concert by singer Lady Gaga in Rio de Janeiro.

Judge Fabiana Pagel of the Rio Grande do Sul state court did not name the suspect in her ruling, but said he is a man investigated by Rio de Janeiro police as the alleged mastermind of the plot.

Police in Rio Grande do Sul state, which borders Argentina and Uruguay, said Sunday they had released a man under investigation for the alleged plot after he paid his bail.

Brazilian media reported that is the same man jailed on Monday by Judge Pagel.

Rio police did not reveal names of either of its two suspects or show images of the explosives that the alleged plotters intended to use. Felipe Cury, secretary of the Rio police, said authorities believed the suspects sought to target Brazil’s LGBTQ community.

The Rio event on Saturday was the biggest show of the pop star’s career, attracting an estimated 2.5 million fans to Copacabana Beach. Security was tight at Saturday’s concert, with 5,200 military and police officers deployed to the beach where fans were reveling.