BALTIMORE -- A Baltimore drug kingpin who inspired characters on the HBO drama "The Wire" has died while serving a term in federal prison in North Carolina.

Baltimore Health Department spokesman Sean Naron confirmed on Tuesday that 54-year-old Nathan Barksdale died in a medical prison in Butner. Naron did not know exactly when Barksdale died, or how. The death was first reported in The Baltimore Sun.

Barksdale ran a heroin-dealing operation in Baltimore in the 1980s, and served 15 years in state prison on a battery charge. "The Wire" creator David Simon has said Barksdale served as inspiration for aspects of some of the show's characters.

In recent years, Barksdale worked with Safe Streets, an anti-violence program run by the Health Department.

In 2014, however, he pleaded guilty to participating in a drug conspiracy and was sentenced to four years.