BRUMADINHO, Brazil — Authorities arrested five people Tuesday in connection with the collapse of a Brazilian mine dam, while the death toll rose to at least 84 and the carcasses of fish floated along the banks of a river downstream that an indigenous community depends on for food and water.

The dam that held back iron ore waste, owned and operated by big mining company Vale SA, collapsed Friday, burying a company cafeteria and other Vale buildings and inundating part of the small southeastern city of Brumadinho.

Lt. Flavio Godinho of the Minas Gerais state civil defense agency said Tuesday evening that the number of confirmed dead had risen to 84 from 65. He said the number of missing stood at 276.

The dead fish and trash were seen by a reporting team for The Associated Press about 11 miles downstream from the dam along the banks of the Paraopeba River.

The Pataxo Indians living alongside the river who use it to fish, bathe and gather water for the plants they cultivate as food were told by Brazilian environmental officials that they should no longer do so, said Hayo, the village chief who goes by one name.

The signs of possible ecological consequences came as the arrests of company workers with links to the dam were made in Sao Paulo and in the state of Minas Gerais.

Three of the arrested worked for Vale, the company said, adding that it was cooperating with investigating authorities.

A German company that has inspected the dam said two of its employees were arrested. The Munich-based TUEV Sued company declined to specify whether the arrested staff were from its German headquarters or its Brazilian branch.

In ordering the arrests, Minas Gerais state judge Perla Saliba Brito wrote that the disaster could have been avoided.

It’s not believable that “dams of such magnitude, run by one of the largest mining companies in the world, would break suddenly without any indication of vulnerability,” the judge wrote in the decision, according to news portal UOL.

Authorities said the five will be detained for 30 days while officials investigate possible criminal responsibility.

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