If this had taken place in a favela in the World Cup city of Rio, I would probably not be too surprised.
Do I read between the lines and get the impression that you think the civilized Brazilians are not to be confused with the black Brazilians?
First of all, the biggest problem of Brazil are not only the slums in big cities, but also the misery in the regions like North and Northeast. Once again, we are talking about Maranhao, one of the states with lower HDI in the whole country.
Yes, this could happen in a slum, but differently from rural cities, slums are very urbanized places where people live near police. People in slums dont kill because of trivial things like a football game, but usually for money and drugs. Yet, we never know what is going to happen. This is the first time we read about such a weird crime like this, but banal reasons to kill another human being could happen in any place.
Also I am not talking about black people, because we dont have many black people living in the state of Maranhao. They are mostly cafuzos or mulatos, a mixture of indian roots with black roots and white roots. Its a different ethnicity than black people, the nordestinos, inhabitants of the states of Maranhao and other states, are usually a mixture of all genres, but usuall they have small stature due to poor nutritional diets. If you want to know where brazilian people suffer more from hunger, its in the called " sertao nordestino", a zone that comprehends the inner regions of Northeast, This is where the crime happened This crime happened in a poor and miserable city located in one of the worst places in Brazil to live.