A terrifying shootout left a man dead at his own birthday party in what police believe could have been politically motivated.

Left-winger Marcelo Aloizio de Arruda was gunned down a hail of bullets at his 50th birthday party in Foz do Iguacu, Parana state, Brazil, on Saturday, 9th July.

His killer – a backer of Brazil’s ruling Liberal Party – had gatecrashed the bash after earlier having threatened to kill “all you bastards”.

Terrifying CCTV footage of the shootout shows the killer – named as prison guard Jorge Jose da Rocha Guaranho, 38 – bursting into the venue.

Da Rocha Guaranho – a hardcore supporter of Brazilian President Jair Bolsonaro – had yelled “Here’s Bolsonaro” before opening fire, guests later told police.

As he begins to fire, victim Marcelo falls down behind tables and chairs as he grabs his own gun and opens fire on his attacker.

The gunman falls to the floor, where he is repeatedly kicked in the head by other partygoers at the venue.

A second video, filmed earlier on a security camera outside the hall, shows how the killer first argues with his victim before leaving the scene.

But Da Rocha Guaranho swiftly returns with a handgun and shoots into the hall as a terrified woman tries to hold him back.

The gunman describes himself on social media as “conservative, Christian” and a Jair Bolsonaro supporter.

He also writes “weapons = defence, no to abortion, no to drugs”.

His victim was an equally hardcore member of the rival, left-wing Workers’ Party, which was the theme of his birthday party.

According to eyewitness accounts and CCTV footage, the killer parked outside the party in a car with a pro-Bolsonaro song blasting.

He pointed his gun out from inside the vehicle while shouting his support for President Bolsonaro.

The victim’s wife, Pamela Suellen Silva, said: “He was manoeuvring the car and suddenly he opens the window and starts saying words like ‘PT garbage, Lula thief, Bolsonaro’…

“That’s when Marcelo went to talk to him, telling him to leave, because there was a private party there, there was only family, and he drew his gun and pointed it at Marcelo and me until he intervened, trying to calm the situation.

“He was with his wife and baby son in the car. His wife asked him to stop too, but he was very bad-tempered.”

According to police spokesperson Iane Cardoso, officers arrived at the venue to find two men injured – Marcelo with two gunshot wounds and Da Rocha Guaranho with three.

Both men were rushed to hospital.

Marcelo died in the early hours of Sunday. He leaves behind his wife and four children.

Parana state public security officials reported on Sunday that Da Rocha Guaranho is still hospitalised in a serious but stable condition under police arrest.

Cops are now investigating the crime, including whether it was politically motivated.