Last spring, in the days following reports of a massacre of Afghan

Last spring, in the days following reports of a massacre of Afghan civilians by a once respected soldier named Robert Bales, Seattle Weekly

talked to a former top Army psychiatrist. There had been speculation that PTSD or a traumatic brain injury Bales had suffered might account for the inexplicable massacre, but Elspeth Cameron Ritchie thought otherwise. Neither malady was associated with that kind of violence.

She pointed to another possible explanation: an anti-malarial drug called mefloquine (also known by the brand name Lariam) that the military continued to use despite reported side effects including hallucinations, suicidal thoughts and psychotic behavior. The military has refused to say whether it gave the drug to Bales, who was stationed at Joint Base Lewis-McChord.

But now, a couple months after Bales pleaded guilty in military court and a month before his sentencing hearing, newly released documents suggest that he did take the drug. As Ritchie reported in a blog she writes for Time, a former colleague of hers, former Army epidemiologist Remington Nevin, received an FDA document through a Freedom of Information Act request that, while not naming Bales, describes a situation that could only refer to the former staff sergeant.

Speaking with SW from Baltimore, where he is currently pursuing a doctoral degree at Johns Hopkins Bloomberg School of Public Health, Nevin explains that the document is a report of what’s called an “adverse event” associated with a drug. This one was submitted to the FDA by Lariam manufacturer Roche, which said it received information from a pharmacist about a soldier with a history of TBI who had been treated with mefloquine.

From the report:

On an unknown date the patient who was a soldier in the US Army developed homicidal behavior and led to Homicide killing 17 Afghanis. It was reported that this patient was administered Mefloquine in direct contradiction to US military rules that Mefloquine should not be given to soldiers who had suffered TBI (Traumatic brain injury) due to its propensity to cross blood brain barriers inciting psychotic, homicidal or suicidal behavior.
Bales pleaded guilty to killing 16, not 17, Afghanis, but otherwise the reference is clear.

Nevin cautions that the report is not proof that mefloquine caused Bales to act as he did, nor even that he took the drug. Adverse event reports are supposed to be filed by health care professionals and others with direct knowledge of a patient’s behavior while on a drug, but regulators do not verify the information. And the reports make no claim of proving causality.

Nevertheless, Nevin, who has long warned against using mefloquine, says it would explain a lot if Bales was given the drug. “Everything he did has been perfectly consistent—almost textbook—of someone intoxicated with mefloquine,” Nevin says.

And we still are left searching for answers more than a year after the massacre. Even as Bales pleaded guilty in June, which took the death penalty off the table, he said he was unable to account for—or even remember—what he did.

If Bales was on mefloquine, why hasn’t his outspoken and flamboyant attorney, John Henry Browne, raised the issue? Browne has not yet returned a request for comment. But it could be that the lawyer is wary of raising the issue in a military court. While the military has dramatically scaled back the use of mefloquine in recent years, it has not fully accepted reports of its ill effects.