The commander of an Iraqi militant group accidentally killed 22 members of his unit Monday who were training to become suicide bombers after he conducted a demonstration with live explosives, the New York Times reported.

The Sunni militants belonged to the Islamic State of Iraq and Syria, also known as ISIS, according the Times. They have been engaged in fighting with the Iraqi government army and conducted suicide bombings throughout the country.

Another 15 members of the group were injured. An Iraqi army official described the commander as a “prolific recruiter,” adding that he was “able to kill the bad guys for once” in Monday’s accident.

The BBC offered a slightly different version of events, reporting that it was a car bomb that accidentally detonated and killed at least 21 insurgents.