An Arkansas pathologist was charged Tuesday for the deaths of three veterans receiving treatment at a local VA hospital.

Dr. Robert Morris Levy was charged after multiple errors had been found in the diagnosis and handling of three patients that resulted in their deaths. Levy also attempted to hide the error by altering case files, all stemming from alleged substance abuse that impaired his ability to act.

Levy was originally fired from the Veterans Health Care System of the Ozarks in Fayetteville, Arkansas, in 2018 after he was arrested for driving under the influence. The arrest also uncovered evidence of Levy’s substance problems, prompting an investigation into the near 34,000 cases he has handled during his time as a pathologist.

It was eventually found 3,000 errors or incorrect diagnoses starting in 2005. Aside from covering the mistakes, the files contained changes designed to hide Levy’s own personal problems with substance abuse.

“In doing so, he was allowed to stay employed with the Veterans Administration, thus earning a salary, benefits and possibly a bonus,” U.S. Attorney Duane Kees said in a press conference.

The most notable mistakes were the three deaths that resulted from Levy’s mistakes. In one case, the patient died from prostate cancer that went untreated after a biopsy Levy used to determine he didn’t have cancer. A second patient then died from squamous cell carcinoma after Levy misdiagnosed and treated him for a different type of carcinoma. And the third patient died from small cell carcinoma after being diagnosed for a different cancer.

Levy has been charged with multiple counts of involuntary manslaughter, fraud, and making a false statement.

“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 Michael Missal said.