The bodies kept coming: 25, 30, 35, 40, 45..., Bruno Itan told BBC Brasil. They included those of police officers.
One of the bodies had been decapitated - others were totally disfigured, he said. Many also had what he says were stab wounds.
More than 120 people were killed during Tuesday's raid on a criminal gang - the deadliest such raid in the city.
Bruno Itan told BBC Brasil that he was first alerted to the raid early on Tuesday by residents of the Alemão neighbourhood, who sent him messages telling him there was a shoot-out. The photographer made his way to the Getúlio Vargas hospital, where the bodies were arriving.
Itan says that the police stopped members of the press from entering the Penha neighbourhood, where the operation was under way. Police officers formed a line and said: 'The press doesn't get past here.'
But Itan, who grew up in the area, says he was able to make his way into the cordoned-off area, where he remained until the next morning. On Tuesday night, local residents began to search the hillside which divides Penha from the nearby Alemão neighbourhood for relatives who had been missing since the police raid.
Residents of the Penha neighbourhood proceeded to place the recovered bodies in a square - and Itan's photos show the reaction of the people there. The brutality of it all impacted me a lot: the sorrow of the families, mothers fainting, pregnant wives, crying, outraged parents, the photographer recalled.
The governor of Rio state said that the massive police operation involving around 2,500 security personnel was aimed at stopping a criminal group known as Comando Vermelho (Red Command) from expanding its territory.
Initially, the Rio state government maintained that 60 suspects and four police officers had been killed in the operation. They have since said that their preliminary count shows that 117 suspects have been killed. Rio's public defender's office has put the total number of people killed at 132.
Criticism has been directed at the operation, with the Office of the United Nations High Commissioner for Human Rights expressing horror at the death toll. The governor defended the police, expressing that they did not intend to kill, but meant to arrest suspects.
The situation surrounding the tragic events continues to evolve, and a hearing has been summoned to investigate the police actions.
