A Marine drill instructor at Parris Island, South Carolina, was under investigation for allegations of mistreating enlistees when he was inappropriately sent back to a new job dealing with recruits, one of whom, a Muslim, died during basic training in what the Corps has ruled a suicide, military documents show.

The drill instructor is alleged to have ordered another Muslim recruit into an industrial clothes dryer as punishment in 2015, several months before Raheel Siddiqui died after leaping from a stairwell at Parris Island after allegedly being abused by the drill instructor.

Siddiqui had threatened suicide in the days before he died, but may not have received appropriate treatment, investigators found.

CNN and other news organizations on Wednesday reviewed hundreds of pages of redacted documents detailing three investigations into abuse allegations at Parris Island.

The drill instructor has not been identified by the Marines because the service is now considering charges against him and as many as 19 others. Some of those could be criminal charges leading to a court martial, two defense officials told CNN.

The documents detail repeated incidents – including the one with the dryer – such as slapping and hitting recruits, and making them do activities from stress positions, all alleged hazing.

The Muslim recruit who was put in the dryer has not been identified, but according to the documents and as first reported in The Washington Post, he suffered burns. Several Marines were subjected to ethnic or homophobic slurs, including Marines assumed to be Muslim being questioned by more senior Marines about whether they were terrorists, the documents say.

Investigation found physical and verbal abuse

The Marines statement said investigations found drill instructors physically and verbally abused recruits and that one drill instructor was improperly assigned for duty while being investigated for allegations of assault and hazing. Investigators found inconsistencies in how the Marines responded to suicidal statements, the Marines said.

The 20-year-old from Michigan died March 18.

The Marines recommended a number of changes, including mandatory suspension of personnel investigated for abusing or hazing recruits and increased officer oversight of training.

CNN’s Keith Allen and Steve Almasy contributed to this report.