The Drug Enforcement Administration has joined the investigation into the death of actress Hayden Panettiere, the New York Times and ABC News reported, citing sources familiar with the matter.

CNN has reached out to the DEA and Greenville Police, which is leading the investigation, and representatives for Panettiere.

Panettiere, a onetime child star who soared to fame while navigating addiction and postpartum depression in her adult life, died Sunday at an apartment in Greenville, South Carolina.

The 36-year-old had addressed her struggles in a memoir and spoke publicly about losing her brother. Months ago, she had described feeling ready to start over, and was making a comeback, with her latest film released in January.

Earlier this week, police released a report that said Panettiere’s boyfriend and his brother called 911 to say the actress was unresponsive at the apartment complex where medics would later declare her dead.