Federal prosecutors from Arkansas charged a former Veterans Affairs pathologist with three counts of involuntary manslaughter in the deaths of former patients whose medical reports he mishandled due to his own substance abuse problems.

The criminal case against Robert Morris Levy also includes numerous charges of fraud and lying to investigators. His arrest comes after more than a year of investigation by the US Attorney’s Office with help from the VA Inspector General’s office.

“These charges send a clear signal that anyone entrusted with the care of veterans will be held accountable for placing them at risk by working while impaired or through other misconduct,” VA Inspector General Mike Missal said in a statement. “Our thoughts are with the veterans and their families affected by Dr. Levy’s actions.”

Levy served as the chief of pathology and laboratory medical services for the Veterans Health Care System of the Ozarks from 2005 to 2018, when VA officials fired him.

According to federal prosecutors, Levy has been under investigation for drinking alcohol while on duty as far back as 2015. In 2016, he entered a three-month in-patient treatment program program, and was reinstated by department and state medical officials on the condition that he remain sober.

But prosecutors allege Levy cheated drug tests and falsified records to cover up his relapses. As a result, he continued reviewing sensitive patient medical information while intoxicated, potentially issuing incorrect or dangerous diagnoses for thousands of veterans.

In at least three cases, investigators believe that directly resulted in patient’s deaths. On two of those occasions, the indictment says, Levy doctored medical records to make it appear that other pathologists agreed with his mistaken work.

Duane Kees, U.S. attorney for the western district of Arkansas, said in a statement that the indictment “should remind us all that this country has a responsibility to care for those who have served us honorably. Our veterans deserve nothing less.”

Earlier this year, officials from the Fayetteville VA hospital said as many as 12 patient deaths may be connected to Levy’s crimes. KFSM reported that nearly 34,000 medical cases that Levy handled during his tenure had been reviewed for mistakes after his firing, with nearly 10 percent showing errors.

Members of Congress have been monitoring the investigation and were informed of the coming indictment last weekend, a Hill staffer said.