As the death toll from the tailings dam collapse at Vale’s Córrego de Feijão mine in Brumadinho, Brazil climbed to 65, Brazilian authorities opened a criminal investigation of the cause of the collapse and arrested five people.

Three of those arrested were employees of the Vale and two more were contractors. Federal and state prosecutors said 30-day arrest warrants had been issued “aiming to establish criminal responsibility for the rupture of dams at the Córrego de Feijão mine maintained by Vale.”

More than 275 people were still missing four days after the collapse and are presumed dead. Vale said it was cooperating with investigators in the case, which has enraged Brazilians and raised fresh questions about the company’s commitment to safety after a similar dam burst just over three years ago at a nearby mine it jointly owned by Vale and BP that left 19 people dead.

Reuters reported that two of those arrested were Vale’s senior managers at the Corrego do Feijao mine, where a tailings dam broke on Friday, hammering the nearby town of Brumadinho with a flood of mining waste - according to a court order seen by Reuters. The job of the third Vale employee was not immediately clear.

Two other engineers, who worked on behalf of Vale and are accused of attesting to the safety of the dam, were arrested in Sao Paulo, state prosecutors there said.

Minas Gerais state investigators issued a total of five arrest warrants and seven search warrants on suspicion of murder, falsification of documents and environmental crimes, a judge’s decision showed.

Chief Financial Officer Luciano Siani said Vale was doing all it could, offering money to mourners, extra tax payments to local government, a special membrane to remove mud from the river and major investments to make its dams safer.

Following a deadly 2015 tailings dam collapse just a few towns over at a mine half-owned by Vale, the disaster remained unforgivable in the eyes of many Brazilians.

At the headquarters for the local mining union, which lost more than one in 10 members by organizers’ count, treasurer José Francisco Mateiro, blamed the company and authorities for putting him and his comrades at risk.

“They call it an accident but the design of those dams was premeditated,” he said. “There have been warnings about all mining dams for a long time now.”

Vale CEO Fabio Schvartsman said the facility was up to code and equipment had shown the dam was stable just two weeks before the collapse.

“We are 100 percent within all the standards, and that didn’t do it,” he said in a Sunday TV interview.

Siani said the company would donate 100,000 reais ($26,600) to each family that had lost a loved one, adding the company would continue paying mining royalties to Brumadinho despite a halt in operations there.

The company was building a membrane to stop the flow of mud now snaking down the Paraopeba River. A “bold” investment plan also would speed the process of making dams more secure, he said.

A presidential task force contemplated forcing out Vale’s management. Government ministers have said Brazil’s mining regulations are broken. The country’s top prosecutor said the company should be criminally prosecuted and executives held personally responsible.