The Marine Corps is looking at possible punishments and courts-martial for up to 20 officers and enlisted leaders in the wake of investigations prompted by the suicide of a recruit at its Parris Island training facility in South Carolina.

The results of investigations released Thursday found trainees — and even some drill instructors — were subjected to repeated incidents of verbal and physical abuse. It also faulted commanders for not paying enough attention to what was going on.

The investigations were touched off by the death of Raheel Siddiqui of Taylor, Michigan, a young Muslim who had told his relatives he wanted to become a Marine to serve his country.