Authorities deployed helicopters and other extra security Tuesday in Rio de Janeiro after members of a criminal gang set fire to at least 35 buses in apparent retaliation for the police slaying of one of their key members. The attack late Monday on public transport buses took place in a western section of Rio far from its tourist districts and caused no casualties, but it represented significant defiance of the government. Rio’s state Gov. Cláudio Castro said Tuesday after a meeting with his security officials that the city was on “maximum alert” with helicopters and drones reinforcing the police presence on the streets.