ISTANBUL -- Three people were arrested on charges of negligence in the Turkish mining disaster that killed 301 people, a prosecutor said Sunday. The suspects are among 19 people still in custody.

Prosecutor Bekir Sahiner said the three were also accused of the crime of causing the death of more than one person, a charge that doesn't imply intent. In a news conference in Soma, where the disaster took place, he said that one of those arrested was the company's operations manager. The manager is Akin Celik, though Sahiner didn't name him.

A total of 25 people were initially detained and six of them have been released, Sahiner said.

The charges can lead to sentences of between three and 15 years in prison, according to the Turkish penal code.

Other company executives were among the detained as Turkish officials investigate the mining disaster. The Dogan news agency reported earlier that Ramazan Dogru, general manager of the mine owned by Soma Holding was detained.

Government and company officials have insisted that the mine was inspected regularly and negligence wasn't a factor in Tuesday's tragedy. But reacting to widespread public anger, government officials promised to investigate and pledged that any mine officials found to be negligent would be punished.

The Milliyet newspaper said Saturday that a preliminary report by a mine safety expert who inspected the Soma mine suggested that smoldering coal caused the mine's roof to collapse. The report said the tunnel's support beams were made of wood, not metal, and the mine had too few carbon monoxide sensors.

Company officials have described safety standards as high, noting that the mine contained 50 gas sensors and employees were provided with gas masks.

On Saturday, Energy Minister Taner Yildiz said rescue workers retrieved the bodies of the last two miners missing in the disaster, putting the death toll at 301. Authorities then sealed the mine entrance with bricks.