A suburban St. Louis man has been sentenced to 20 years in federal prison for providing the heroin that killed a user.

A judge on Thursday sentenced 36-year-old Anthony Marion of St. Charles. He pleaded guilty in February to distributing heroin resulting in death.

Court documents say Marion provided heroin to Lauren Martinez, who subsequently provided it to the victim in February 2016. Martinez has pleaded guilty to heroin distribution and faces sentencing Friday.

The U.S. Attorney's office in St. Louis says that even after Marion and Martinez learned of the death, they continued to distribute heroin. Marion was arrested following an undercover operation.