The Sao Paulo policemen did not know they were being filmed on an amateur video, shown on Monday on the big Globo TV channel. In a separate incident, filmed at the same roadblock on a different night, the same policemen were seen beating a man with clubs before taking him behind a wall. The video sound recorded screams and a gunshot and the cameraman said he later found the man wounded.
The latest case of brutality by Sao Paulo's military-led police outraged but hardly surprised Brazilians. Human rights groups have long described the Sao Paulo police as one of the world's most violent.
Nine of the 10 officers seen on the videos, recorded in the city's poor Diadema suburb, have been detained by the military police pending trial. After public fears that they would get off lightly before a military tribunal, Mario Covas, Sao Paulo's state governor, said they would be tried by a civilian court.
Mr Covas apologised to the public but sought to portray the incident as isolated. Most Brazilians scoffed. "This kind of stuff happens all the time. The only difference this time is that it's down on film," said James Cavallaro of the human rights group Americas Watch.
"This was in no way an isolated incident," added Congressman Jose Anibal. "It happens all the time. I hope this leads to an end to the impunity policemen like these have enjoyed for so long."
"They are nothing more than bandits in uniform," said state prosecutor Luiz Antonio Marrey. "They are cops turned into criminals since they've committed murder, assault, extortion and abuse of authority."
Witnesses said the police had beaten drivers who refused to pay bribes to allow them through the roadblock. "The authors of this barbarity must receive exemplary punishment," said Ricardo Balestreri of Amnesty International Brazil.
Sao Paulo's military-led police gained notoriety in 1992 when they put down an inmates' revolt at Carandiru prison to put down an inmates' revolt. More than 100 prisoners died.