Child actor Sophie Nyweide, who was found dead in the woods last week, was pregnant, according to a death certificate obtained by PEOPLE.

Nyweide, 24, was pronounced dead before 5 a.m. on April 14 in Bennington, Vermont, the magazine reported. An autopsy was performed, but the cause of death is still unknown. Police are investigating the death of Nyweide as an unintentional overdose.

PEOPLE spoke with Nyweide’s mother, Shelly Gibson, who said she knew her daughter was using drugs and was with other people when she died, though she didn’t know their identities.

Authorities were called to a “wooded area along the banks of the Roaring Branch River” after someone reported an unresponsive female, Vermont Office of Chief Medical Examiner, Paul Doucetter, the chief of police for Bennington, Vermont, told USA Today.

That same person who called 911 stayed on the scene and is cooperating with authorities, police told the news outlet.

The circumstances of Nyweide’s pregnancy, including her stage, were unclear, according to PEOPLE.

Born in Burlington, Vermont, on July 8, 2000, Nyweide began acting early, with her first role being Bella in the 2006 film, “Bella.” She then played Jackie Vidales in Mammoth and the younger sister in “Noah,” which came out in 2014, according to IMDb.

“Sophie was a beloved daughter, granddaughter, sister, friend and new aunt,” Nyweide’s family wrote in an obituary according to CNN. “Creative, athletic and wise beyond her years, Sophie accomplished so much in the time she danced upon earth (literally-she danced as she moved!).”