A Russian conscript who shot dead eight fellow soldiers at his army base last year said on Thursday he had been left with no other course of action after conscripts turned his life into a living “hell.”

Ramil Shamsutdinov opened fire on servicemen at a military facility in the Far East region of Zabaikalsk on Oct. 25. He was detained shortly after the incident, has admitted his guilt and could face life in prison if convicted.

The case is embarrassing for the military, which has been revamped in recent years at great cost, projects an image of might and says it has stamped out the Soviet-era problem of hazing — the bullying of conscripts by older soldiers.

Defense Minister Sergei Shoigu, who some tip as a possible successor to President Vladimir Putin, told Russian media last year that extensive army reform had prevented hazing altogether.

“I regret I couldn’t restrain myself and that I resorted to this extreme step, but I had no other way out. I couldn’t take any more mistreatment,” Shamsutdinov wrote in an open letter circulated by his lawyer Ruslan Nagiyev on social media.

“I didn’t expect to end up in such hell. There was nowhere to run and complain,” he wrote, without providing details.

Some Russian media have quoted Shamsutdinov as saying that he had been threatened with rape and that officers were beating up conscripts and taking their money.

Russian men aged 18-27 are legally required to serve one year in the army. Some Russians go to lengths to dodge the draft in part because of fears of hazing despite the government’s drive to overhaul the military.

Shamsutdinov said he had wanted to serve as a conscript and then join the army as a career. He apologized to the families of his victims.

Lawyer Nagiyev said last month police were investigating whether Shamsutdinov and several other soldiers had been subjected to hazing and had opened a separate criminal case.