Turkish authorities on Thursday arrested 25 suspects, including the director of a state mine in northwestern Turkey, after an explosion killed 41 there this month, local media reported.

The explosion tore through the mine on October 14 near the small coal town of Amasra on Turkey’s Black Sea coast.

The director of the mine, Cihat Özdemir, was among the 25 detainees, according to the Anadolu news agency.

President Recep Tayyip Erdogan has pledged a full investigation into the blast, saying “no one will be spared” if the accident report establishes who is responsible.

Relatives of the dead told AFP and Turkish media that miners complained about the smell of gas in the mine about 10 days before the blast.

The opposition accuses the government of not having taken the necessary measures to prevent the disaster.

Turkey suffered its deadliest coal mining disaster in 2014, when 301 workers died in an explosion and subsequent fire that collapsed a mining shaft in the western city of Soma.