Rioters attack police on historic Protestant holiday . The violence erupted after a Catholic priest was shot dead in the city of Rio de Janeiro by two men who said they were protesting against his support for Brazil's new leftist government. People throw objects and explosives . Disruption began on eve of holiday .
Rioters attack police on historic Protestant holiday . At least 27 police injured in two different locations , including three hit by shotgun blast . People throw objects and explosives . Disruption began on eve of holiday .