Jac Souza dos Santos, 30, surrendered to authorities following an hours-long standoff with police where he made a list of demands including political reform in the country and the extradition of an Italian guerrilla fighter.
"The biggest worry for us was the lack of concrete demands. This was a constant worry to the negotiator,” said police delegate Paulo Henrique who commended the "calmness of the victim and excellent work of negotiators."
Television images captured Santos as he paraded his unidentified 50-year-old male hostage on the balcony of a room on the 13th floor of the upscale Saint Peters Hotel. The hostage was wearing what was believed to be an explosive vest but was later determined to be fake. The gun was determined to be a toy.
"We believed during the negotiations that an explosion was possible ... He (Santos) said throughout that he would do it," Henrique said.
The victim was taken to a hospital to be evaluated as Santos headed to the police station.
Santos, who lost a 2008 campaign for city councilman in Combinado in the state of Tocantins for the Partido Progressista (PP) party, entered the hotel, in Brasília’s central hotel district, at around 9 a.m. local time (1200GMT), police said, and 300 guests and workers were evacuated shortly afterwards.
His list of demands included that President Dilma Rousseff not be re-elected next month, and thatBrazil's "Ficha Limpa, or "Clean Record" law be fully implemented.
The law, which bans candidates with a corrupt or criminal past from running for office, was passed in 2010. Some candidates were banned from running during municipal elections in 2012, and this year will be the first national-level election with the law in place.
He also demaned the extradition of Cesare Battisti, an Italian leftist guerrilla convicted of four murders there in the 1970s. Brazil has refused to send Battisti back to Italy, allowing him to stay as a political refugee.