Following a catastrophe that left 301 coal miners dead, Turkish officials arrested four people, including three company executives, on Friday and detained 25 others. The executives were brought up on charges of negligence after investigators found evidence suggesting that the company ignored warnings about safety.

One of the three arrested is the mine’s manager. The others are two engineers and a security official. The mining company’s owner, a technical consultant, and shift directors were also taken in to custody. The charges carry between three and 15 years in prison.

The disaster has catalyzed protests against Turkey’s government, which were already in a state of agitation over corruption allegations against Prime Minister Recep Tayyip Erdogan. Security has been placed around the mine to prevent protesters from gathering there.