WELLINGTON, New Zealand (AP) — A shocking Australian military report into war crimes has found evidence that elite Australian troops unlawfully killed 39 Afghan prisoners, farmers and civilians.

Australian Defence Force Chief Gen. Angus Campbell said Thursday the shameful record included alleged instances in which new patrol members would shoot a prisoner in order to achieve their first kill in a practice known as “blooding.” He said the soldiers would then plant weapons and radios to support false claims the prisoners were enemies killed in action.

Campbell said the illegal killings began in 2009, with the majority occurring in 2012 and 2013. He said some in the Special Air Service encouraged “a self-centered, warrior culture.”

He said the report recommended 19 soldiers be investigated by police for possible charges, including murder.

The chief was announcing the findings of a four-year investigation by Paul Brereton, a judge who was asked to look into the allegations and interviewed more than 400 witnesses and reviewed thousands of pages of documents.