There were fewer murders in Brazil's second city of Rio de Janeiro last year - but the number of killings by police has soared.

Killings by police are at their highest levels since the 1990s, with an average of five people a day killed by officers.

Rights organisations say many officers have killed people in self-defence but some are engaging in summary executions.

Innocent civilians are often getting caught in the crossfire, as Al Jazeera's John Holman reports.