Rio is unruly at best, and Carnival -- Brazil's raucous five-day celebration of drinking, dancing and nudity, which is in its third day, provides an escape, as well as a source, for poverty-stamped violence.
The celebration reaches its midpoint Sunday ahead of next week's climax and the start of Lent's 40 days of contemplation and self-denial.
When the highlight of the celebration, the samba competition, begins after nightfall Sunday -- a group whose leader was murdered on Tuesday -- will still perform.
Revelers stayed up most of Saturday night, dancing in the streets to Eight Ball, a group formed in 1918 and one of the oldest samba music groups in Brazil.
Most drinkers held their beer, but police were on guard this year in Rio, with well earned worldwide fame for the celebration of excess, especially after dusk.
Rio authorities said they plan to put more police on the street, especially late Sunday and Monday, during the contests for best samba school.
For the judging, Brazil's top 13 samba schools will meet at the specially built sambodromo, a stadium that holds 70,000 spectators.
Each school has huge, fantastic floats, each with as many as 4,000 costumed dancers wearing enormous headgear, feathers, sequins and little else. Decorations, composers, seamstresses, carpenters and engineers for just one of these groups can top a million dollars.
The participants are predominately from the slums on Rio's hillsides, and the sponsors of these shows often run drugs or illegal betting rackets.
Unfortunately, it's not all revelry: Gang conflicts sometimes play themselves out at Carnival.
On Tuesday, Guaraci Paes, 42, the vice president of the samba group Academicos de Salgueiro and his wife were murdered by unknown gunmen who riddled their car with bullets outside the group's headquarters in Rio.
Medical reports determined that the killing had the trademarks of an execution. Police suspect it was a revenge killing between gang leaders seeking to control finance of the samba schools.
Paes' brother, Valdomiro, who also led the Salgueiro samba school, was killed three years ago in a crime police linked to a conflict between illegal slot machine bosses.
And four months ago, in another suspected hit, the president of samba school Estacio de Sa, the pride of the slums of Morro de Sao Carlos, was murdered.
Violence beyond the slums and far from Carnival was the death of Joao Helio, six, who was dragged seven kilometers (four miles) to his death by a seat belt on his mother's car, as it was being hijacked.
On the weekend, the Portela and Vila Isabel samba schools silenced their drums for one minute during their rehearsals in memory of Joao. A samba school made up of children memorialized him in a special parade Friday.
Samba school Porto da Pedra's theme will be post-apartheid South Africa with a special nod to Nelson Mandela.
Beija Flor will celebrate Brazil's racial mix, a common Carnival theme. Mangueira, with 4,000 dancers, will tackle another much-loved subject: the Portuguese language spoken in Brazil.