A former Waterloo man has been sentenced to 40 years in federal prison for selling heroin to a woman who died of an overdose.

Eric DeAngelo Griggs, 40, was sentenced for the death of a Cedar Falls woman in 2018, the Waterloo Cedar-Falls Courier reported.

In handing down the sentence, U.S. District Court Judge C.J .Williams said Griggs had to know that heroin and other opioids are potentially lethal.

Griggs was found guilty in April of of distribution of heroin resulting in death and use of a telephone and Facebook Messenger to facilitate heroin distribution. The judge also ordered him to pay $16,000 in restitution to the woman’s family.

The judge also found that Griggs obstructed justice by sending a threatening letter to a person he thought was cooperating with investigators, and prosecutors noted he had a several prior convictions for drugs, fraud and other offenses.

Authorities said Griggs sold heroin to the woman on Aug. 31, 2018. She was found dead the next day. An autopsy determined she died of heroin intoxication.

During the hearing, Griggs continued to maintain he is innocent.