(Radio Iowa) – A man who sold a fatal cocktail of illegal drugs to a woman in Dubuque last year has been sentenced to 20 years in federal prison. Court documents show 30-year-old Carl Ravon Watkins admitted he told the woman he was selling her heroin. Watkins actually sold the woman a mixture of fentanyl AND acetyl fentanyl, which is 15 times more potent than morphine.

The woman took the drugs later that night in her home. A few hours later, her boyfriend found her dead. Dubuque Police set up a sting a day later and, as Watson was arrested, prosecutors say he dropped a baggie containing the same mixture of drugs.