Terrifying moment Brazilian mansion owner opens fire on cop who he confused for a robber causing a deadly firefight that kills three people including police officer and security guard

The owner of a mansion, his security guard and a police officer are all dead after the homeowner confused the agent for a thief and opened fire in Brazil.

Rogério Saladino, 56, was hosting a party at his residence in the high-end São Paulo neighborhood of Jardins when he shot dead civil police investigator Milene Bagalho, 39, on Saturday.

Alex Gomes, 49, who was in charge of the mansion's surveillance was shot during a confrontation with Bagalho's partner after he Saladino had been wounded.

Bagalho, a mother of a five-year-old girl, and Saladino were rushed to an area hospital, where they were pronounced dead. Gomes died on the scene.

Surveillance camera footage showed Bagalho standing on a sidewalk as she was investigating the area following a robbery at a home near Saladino's mansion after a thief stole a vehicle and personal belongings.

Saladino, a father to a 15-year-old boy, could be seen raising a garage door before he opened fire and struck Bagalho.

Bagalho was struck twice in the right arm and once in the right armpit and was unable to respond with fire, the police said. Her partner fired at Saladino and struck him in the chest. Gomes responded by taking Saladino's gun and was shot on the shoulder before he could open fire.

The São Paulo State Department of Homicide and Personal Protection said that Bagalho and her partner had approached neighborhood residents for access to their surveillance cameras and came across Gomes and asked if they could review the mansion's security system.

Gomes told another guard at the home and he notified Saladino. Saladino saw the cops on camera and was not convinced that they were law enforcement agents.

He fired multiple warning shots in the air to scare the cops away and then opened the mansion's gate and shot at Bagalho.

Civil Police Chief Fábio Pinheiro told Brazilian news outlet G1 that Saladino, who had a license to store guns at his home, was 'wrong' in firing at the cops.

'He [Rogério] thought it was a scam but he did everything wrong. He was safe inside his house,' Pinheiro said. 'The house has an armored guardhouse, the gates were all closed if he suspected anything what should he have done, call the Military Police, call the Civil Police.'

Saladino had a .380 pistol registered under his name and illegally owned a .45 caliber pistol.

'He simply opened [the gate], took cover and started shooting at the police officer, who was even talking to her deputy [by phone], reporting the investigation,' Civil Police chief general Arthur Dian said, according to Metropoles news outlet.

He was arrested on murder and assault charges in 1989. In 2008, he was apprehended on an environmental crime. Both cases had been closed, police said.

Saladino was a partner and president of clinical analysis laboratory Grupo Biofast. He leaves behind a 15-year-old from a previous relationship.

Pinheiro said that out of the 650 police officers under his command, Bagalho stood out among all of them.

'Of every 10 robberies we attended to, she and her partner resolved 8. It's an irreparable loss,' he said.