(CNN) Sergeant 1st Class Charles Martland, the Green Beret being separated involuntarily from the U.S. Army for kicking and body slamming an Afghan police commander he describes as a "brutal child rapist," began telling his side of the story Monday.

Martland is under a gag order imposed by the Pentagon, but at the request of Rep. Duncan Hunter, R-Calif, he wrote a statement detailing his actions on Sept. 6, 2011, which was obtained by CNN.

"Kicking me out of the army is morally wrong and the entire country knows it," Martland writes. Last week the Army rejected his appeal.

Martland and former Captain Daniel Quinn were disciplined by the Army after they beat a powerful local police official who they concluded had been raping a small boy. They say they had been encouraged by higher-ups that there was nothing to do about such horrific acts, that these were Afghan problems for the Afghan authorities to work out.

But the Afghan authorities wouldn't do anything about it, the two soldiers say.

Read More