WASHINGTON -- A former Army staff sergeant who pleaded guilty to killing 16 non-combatants while deployed in Afghanistan is asking for a new civilian trial – claiming that he was under an altered mental state at the time due to traumatic brain injury, PTSD and psychosis caused by the anti-malarial drug mefloquine.

Former Army Staff Sergeant Robert Bales is currently serving a life sentence at the United States Disciplinary Barracks on Fort Leavenworth, Kansas, after pleading guilty to 16 counts of premeditated murder committed while deployed with the U.S. Army in Afghanistan. Bales’ attorneys said he pleaded guilty to avoid the death penalty.

Since his conviction, Bales’ defense team has argued that neither they, nor the court, were aware of the “involuntary mefloquine toxicity” Bales was suffering at the time.

RELATED | Anti-malaria drug blamed for massacre by Army sergeant

At the time of the attack, Sgt. Bales was on his fourth combat tour, with a total of 42 months in a combat zone. After his first deployment to Iraq in 2004, he complained about memory loss and depression. After subsequent deployments, according to the brief, he suffered from insomnia, irritability, anger, and memory impairment. His lawyers believe mefloquine may be responsible for at least some of those symptoms.

"Mefloquine is a potential game changer in the Bales case because like in any criminal prosecution, one of the main, important pieces of the case is the accused’s state of mind," John Maher, one of Bales’ lawyers, told WUSA9 last year.

RELATED | National Academies to study long-term psychiatric effects of antimalarial drugs

Mefloquine was for years a widely prescribed medication for soldiers and travelers in areas of the world at high risk for malaria. In particular, it was the go-to anti-malaria medication for the U.S. military in malaria-prone regions like Afghanistan.

A WUSA9 investigation also found dozens of Peace Corps volunteers deployed around the world who said they’ve suffered devastating side effects from mefloquine that they were told to take or be sent home.

WUSA9 INVESTIGATION | Veterans allege devastating side effects from anti-malaria drug they were ordered to take | The Peace Corps and anti-malaria drugs: What you need to know | ‘I offer myself:’ Vets urge committee to take serious look at anti-malarial drugs

Amid concerns about possible serious neuropsychiatric side effects from the drug, the U.S. military began prioritizing the use of other antimalarials in 2009. In 2013, the FDA added a black box warning to mefloquine, noting that side effects – among them nightmares, visual auditory hallucinations, anxiety, depression and suicidal ideation – may persist even after the medication is discontinued.

Bales pleaded guilty to murder in his case the same year the FDA first added the black box warning to mefloquine. His lawyers now believe that if the side effects of the drug had been better understood at the time, Bales’ case might have gone a different way.

“If Bob Bales were under a drug, a prescription drug that compromised his state of mind, that means by law, he can’t be guilty," Maher said.

Bales initially appealed his plea to the U.S. army Court of Criminal Appeals, and then to the U.S. Supreme Court. In June, SCOTUS declined to accept the case – effectively ending his options through the military trial system.

On Monday, Bales’ attorneys’ filed a petition for a writ of habeas corpus – a request for a court to accept a case – in the U.S. District Court for the District of Kansas.

The petition requests a civilian trial to review Bales’ court-martial convictions and sentence. Under federal law, civilian courts can accept and review servicemembers’ cases after they have exhausted their military review options.

Chief among their arguments for such a review is that the competency board “failed to assess evidence of mefloquine psychosis” in Bales. They argue that could mean his guilty plea was not “knowing, intelligent and voluntary.” They also say the court ignored testimony from medical experts about the effects of mefloquine psychosis on Bales’ state of mind on the night of the murders.

Federal prosecutors have until July 26 to file a response arguing why Bales should not receive a civilian trial.

---

Jordan Fischer is an investigative reporter with WUSA9. Follow him on Twitter at @JordanOnRecord.