What to Know With around two milligrams of fentanyl needed to kill the average adult, that amount would have been enough to kill around 14,000.

A Southwest Florida man is behind bars for the second time after he sold undercover officers heroin – this time after tests showed it contained enough fentanyl to kill 14,000 people.

NBC affiliate WBBH-TV reports that 24-year-old Jhonni August was arrested this week, nearly one month after Collier County Sheriff’s deputies arrested him for selling an ounce of the drug to undercover deputies in East Naples.

The department said further tests revealed the drug contained over 29 grams of the highly dangerous drug traditionally added to heroin to increase its potency.

With around two milligrams of fentanyl needed to kill the average adult, that amount would have been enough to kill thousands more and August was arrested on Wednesday.

August remains behind bars with his next court date set for August 12th.