ST. GABRIEL, La. (KLFY) — A former Lafayette doctor convicted of attempted murder by injecting his former mistress with HIV-tainted blood has died, authorities said.

Richard J. Schmidt, 74, died at a Baton Rouge hospital Feb. 12, according to Ken Pastorick, spokesperson for the Louisiana Department of Public Safety and Corrections.

Schmidt was incarcerated at Elayn Hunt Correctional Center in St. Gabriel, Pastorick said.

The former doctor was convicted in 1998 of using HIV- and Hepatitis C-tainted blood from two patients to inject his ex-mistress, Janice Trahan, under the guise of giving her a Vitamin B-12 shot.

According to court records, the DNA in the HIV in Trahan’s blood was the same as that of a patient of Schmidt’s, evidence that led to the conviction. It was the first time in a U.S. criminal court that viral DNA was used to prove a connection between two HIV-positive people.

Schmidt was sentenced to 50 years in prison for the crime.