The decision was based on the medical examiner's determination as well as the findings of the investigation, Greenville police said in a statement.
Panettiere, who starred in the TV series Heroes, was pronounced dead in an apartment in Greenville on August 16 at age 36 after paramedics found her unresponsive.
A coroner's report last month said her death was from an accidental overdose of several drugs, including fentanyl. Panettiere's on-and-off boyfriend, Brian Hickerson, and his brother Zach Hickerson were with her when emergency services arrived, according to a police report.
It remains unclear whether US authorities may still be examining the case separately.
In a petition to a California court last month, Panettiere's ex-fiance, former boxer Wladimir Klitschko, said some of her property had been taken by US law enforcement agents investigating her death and by an unnamed non-relative looking to sell it.
Greenville police sergeant Diana Munoz said she could not comment on whether any other agencies were investigating.
The California court granted Klitschko legal status this month to protect Panettiere's property for their 11-year-old daughter, who is her sole heir.
In her memoir published in May, Panettiere acknowledged being addicted to alcohol and having postpartum depression after her daughter's birth in 2014. The girl went to live with Klitschko full-time when she was two.
Panettiere's father told investigators that at the time of her death, she had plans to visit her daughter in Ukraine days later.
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