Five police officers in Rio de Janeiro have been arrested after a cellphone video showed them altering a crime scene to justify the extrajudicial killing of a teenager.

The officers allegedly shot 17-year-old Eduardo Santos in the Providencia favela and then left a gun in his hand to make the killing look like self-defence.

As the youth lay dying in a pool of blood, a resident filmed one of the officers putting a pistol into his hand, then firing twice so that gunpowder residue was on the victim’s skin.

“That could have been my child! That’s the UPP! The bogus UPP!” lamented the woman who filmed the incident, referring to the Portuguese initials for the Pacifying Police Units that are supposed to be bringing peace to Rio’s favelas.

The clip went viral on social networks, prompting local media to interview witnesses who supported the accusations of a frame-up.

“He was armed but he surrendered,” a Providencia resident told the Globo TV network. “After he raised his hands, they shot him.”

The officers involved in the shooting registered the killing as a case of justifiable self-defence.

Hundreds of residents staged a protest on Wednesday, demanding justice.

The five police – Eder Ricardo de Siqueira, Gabriel Julian Floriado, Riquelme Paul Gerard, Paulo Roberto da Silva and Pedro Victor da Silva – have been charged with fraud and taken to a military police prison.

In a statement, Rio de Janeiro state security secretary Jose Mariano Beltrame condemned the killing and promised “exemplary punishment” for the five officers.

Brazil’s police kill more and are killed in greater numbers than police anywhere else in the world. Reports of execution-style killings are commonplace, but it is usually only when incidents are filmed that justice is done. The majority of the victims are black or mixed-raced youths from favelas.

In the state of Rio de Janeiro alone, more than 300 people were reportedly killed by police in the first six months of this year.