The actress died, aged 36, at an apartment in Greenville, South Carolina, on August 16.
Brian Hickerson, her former partner has now broken his silence on Panettiere's passing, through his attorney Sloan Ellis.
In a statement given to TMZ, Ellis said: "Hayden's death remains under investigation and it is important to allow that investigation to proceed.
"As has been publicly reported, police confirmed there were no signs of foul play. Out of respect for Hayden's loved ones and the ongoing investigation, there will be no further comment at this time."
Panettiere was found unresponsive, and was pronounced dead at the scene after resuscitation efforts failed.
No official cause of death has yet been released, but dispatch audio that has been released showed discussions of "overdose" and "cardiac arrest".
An insider has claimed that the Nashville star reconnected with Hickerson around two weeks before she died, and they had spent a week together in Los Angeles before heading out east.
A source told Page Six: "He was supposed to leave, but somehow, they ended up on a flight to South Carolina, where he is from."
Panettiere's close friends were said to have been "always concerned" about her relationship with Hickerson, describing him as 'bad news'.
Another source said: "If Brian was back in her life then it was something she was hiding because she wasn't speaking about it with many of her friends."
Panettiere had an 11-year-old daughter with former partner Wladimir Klitschko
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