Autumn Oxley Crittendon’s cause of death has been determined.
The 16 and Pregnant star—who died July 20 at her home in Henrico County, Va.—died due to drug toxicity from fentanyl and para-fluorofentanyl, an illicit synthetic opioid, according to the Virginia Department of Health, per TMZ. The health department also classified the nature of Autumn’s death as accidental.
Many illegal synthetic opioids—which create pain-relieving effects—are “more potent than morphine and heroin,” according to the Drug Enforcement Administration, and therefore can result in overdoses.
Autumn—who appeared on the MTV series’ fifth season in 2014 with her then-boyfriend Dustin Franklin ahead of the birth of their son Drake, now 10—was found unresponsive in her Virginia home in July.
“Once on scene, officers and fire personnel located an adult female unresponsive within the residence,” the Henrico County Police Division told E! News in a statement. “Members from Henrico Fire attempted life-saving measures however they were not effective. Autumn Oxley, 27, of Henrico, was pronounced deceased at the scene.”