Editor's note: This story was first published at 6:41 p.m. EDT on June 29, 2016.

More than a dozen drill instructors at Marine Recruit Depot Parris Island, South Carolina, are under investigation for violating orders on hazing, abuse and lack of proper supervision three months after a 20-year-old recruit died during boot camp .

The announcement follows a series of firings at the Marine Corps' fabled recruit training depot after Raheel Siddiqui died just days after arriving at boot camp.

"The allegations, against approximately 15 drill instructors and affiliated leadership, identify potential violations of Marine Corps orders to include hazing, physical abuse, assault and failure of supervision," officials with Training and Education Command, which oversee both recruit training depots, said in a Wednesday statement. "The investigations date back to November of 2015 and appear isolated to companies within the 3rd Recruit Training Battalion."

Siddiqui was assigned to 3rd Recruit Training Battalion at the time of his death.

All of the Marines under investigation are currently assigned to duties in which they have no direct interaction with recruits, the statement says. But that wasn't the case when Siddiqui, a Muslim, was at boot camp, according to a Wednesday report from The Wall Street Journal.

"One of the critical questions in the internal probe, according to Marine officials, is how Mr. Siddiqui ended up under the supervision of a senior drill instructor who was already under scrutiny for alleged hazing involving minority recruits," the story states. "In one instance, the instructor faced allegations of putting another Muslim recruit in a clothes dryer and making racially charged remarks, according to multiple Marine officials."

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Siddiqui died March 18 after falling nearly 40 feet in a barracks stairwell. Rep. Debbie Dingell, D-Mich., has asked Marine Commandant Gen. Robert Neller if hazing was a factor in the recruit's death.

"During the course of the Recruit Siddiqui death investigation, facts revealed a drill instructor was improperly placed in charge of recruits while he was subject to an ongoing investigation," the Marine Corps' statement says. "Existing orders, policies and procedures to prevent improper assignments were not followed. Interim corrective actions have already been taken."

When the investigations into Siddiqui’s death are complete, Maj. Gen. James Lukeman, head of TECOM, will decide which "appropriate administrative and judicial actions" to take . There are currently three ongoing investigations, according to Marine officials. One of those investigations is being led by the Naval Criminal Investigative Service. The other two are being conducted by the Marine Corps.

"We take every allegation of misconduct very seriously and will review each investigation carefully," Lukeman said in the statement. "MCRD Parris Island and MCRD San Diego are Marine Corps institutions entrusted by the American people to transform the best of our nation's young men and women into U.S. Marines. Every day, approximately 1,000 drill instructors at our recruit depots are doing exactly what they were screened, selected and trained to do in a professional, appropriate manner."

So far, at least two leaders at Parris Island have been fired in connection with an investigation into Siddiqi's death: Col. Paul Cucinotta, former head of the Recruit Training Regiment, and Sgt. Maj. Nicholas Deabreu, the regiment's former top enlisted leader.

Brig. Gen. Terry Williams, Parris’ Island commanding general at the time of the incident, was initially slated to lead Marines in Okinawa, Japan, but was reassigned to a stateside position, according to a Marine official . The reason for his reassignment was not immediately clear.

Lukeman stressed that the safety of Marine recruits and the boot camp training are "among our top priorities."

"Once the investigations are complete, we will take necessary administrative and judicial action as warranted to ensure proper accountability," he added.

But some have become concerned that the rash of firings at Parris Island will harm recruit training.

"The DIs are going to be walking on eggshells, worried if they do this or that they'll get in trouble, and we don't want that," a retired senior enlisted Marine with several tours in the service's recruit training environment told Marine Corps Times earlier this month.

He urged the new leadership at Parris Island to explain the firings so that drill instructors don't feel they have to "look over their shoulders."

"The perception can be that all of the drill instructors are messing up, and that's why leadership is being relieved," he said. "That's the last thing we want. I'm confident the Marine Corps' leadership will continue to give those DIs the confidence to continue to train recruits by [standard operating procedures], to ensure the right individuals are earning the title and the eagle, globe and anchor."

Raheel Siddiqui, 20, died after he fell nearly 40 feet in a barracks stairwell. Rep. Debbie Dingell, D-Mich., has asked Marine Commandant Gen. Robert Neller if hazing was a factor in Siddiqui's death.

The Wall Street Journal first reported on Wednesday that Siddiqi was assigned to a senior drill instructor who was being investigated for hazing.