Hayden Panettiere would have been 37 today: Latest on her death

Tributes began to pour in on Friday, August 21, the day that would have marked Hayden Panettiere’s 37th birthday.

The "Nashville" and "Heroes" star died Sunday, a day after departing from Los Angeles on a plane with her on-again, off-again boyfriend Brian Hickerson, TMZ reported. 

Hayden Panettiere honored on what would have been her 37th birthday

What they're saying:

A Reddit post honoring Panettiere on what would have been her 37th birthday garnered well over two thousand upvotes as of early Friday morning, with over one hundred comments from fans sharing their grief and memories of the actress. 

The latest on Hayden Panettiere’s death

Big picture view:

Hickerson’s attorney issued a statement on Thursday following the death of Hayden Panettiere, saying the circumstances surrounding her death remain under investigation.

Sloan Ellis, of the Ellis Hinton law firm, said in a statement to TMZ that it is important to allow the investigation to proceed. 

"Hayden's death remains under investigation and it is important to allow that investigation to proceed," Ellis said in the statement, adding, "As has been publicly reported, police confirmed there were no signs of foul play."

He continued, "Out of respect for Hayden's loved ones and the ongoing investigation, there will be no further comment at this time."

Hayden Panettiere dies Sunday

Dig deeper:

Panettiere died on Sunday, a day after departing from Los Angeles on a plane with Brian Hickerson, TMZ reported. 

"It is with profound sadness that we share the tragic passing of our beloved Hayden. She was an incredible light and a force of nature who brought immeasurable love and joy to all who knew her -- and to the millions who watched her onscreen," Panetierre’s representative told ABC News.

RELATED: Hayden Panettiere's friends and former co-stars share tributes

Officers and emergency medical personnel responded to a report of an unresponsive woman at the Judson Mill Lofts in Greenville, South Carolina, shortly before 2 p.m. Sunday, the Greenville Police Department said in a statement obtained by The Associated Press.

Life-saving measures were performed, but Panettiere was pronounced dead at the scene, according to the statement.

Police said an acquaintance of the 36-year-old actress called 911 from the apartment complex.

Hayden Panettiere’s preliminary autopsy released

The next day, on Monday, Panettiere’s preliminary autopsy results were released and found no signs of trauma contributed to her death. 

RELATED: Hayden Panettiere's preliminary autopsy released: What it says

"First responders and Emergency Medical Services arrived on scene and located a female in cardiac arrest," the Greenville County Coroner’s Office said in a statement. "EMS personnel initiated advanced cardiac life support measures; however, resuscitation efforts were unsuccessful, and the individual was pronounced deceased at 2:32 PM."

The Greenville County Coroner’s Office and Greenville City Police Department launched parallel investigations into her death.

"At autopsy no signs of trauma were discovered that would have contributed to the death," the coroner's statement continued. "The cause and manner of death remain pending further investigation and the completion of additional studies."

Sources with direct knowledge told TMZ that Hickerson and Panettiere were both inside an Airbnb in Greenville, when Hickerson’s brother Zach Hickerson entered the residence and found Panettiere in a chair in the living room.

Hayden Panettiere’s former fiancée issues statement

On Tuesday, Wladimir Klitschko mourned his former fiancée Panettiere, saying the actress remained an "important part" of his life and promised to keep her memory alive for their daughter, Kaya.

"Our family is going through a time of profound shock and grief," the Ukrainian former heavyweight boxing champion wrote on Instagram after Panettiere’s death at 36. "She left this world far too soon."

Klitschko, 50, said that although Panettiere was "no longer my partner," nothing could erase the time they shared or her place in their lives.

"To our daughter Kaya, I will always speak of her mother with respect and make sure she remembers the person she was," he wrote.

Police report offers more details on her death

On Tuesday evening, a police report released revealed more details into her death.

The police report, which was heavily redacted, said the responding officer first spoke with Zach, who said the woman was his brother’s girlfriend.

After she was declared dead, the officer escorted the brothers out of the apartment. The officer spoke with Brian "more in depth," but the details of that conversation were redacted in the police report.

Also redacted was a list of medications that Panettiere had been taking.

"I observed Zach to be very emotional while EMS were working on Hayden. Brian did not become emotional until EMS declared her officially deceased," the officer said.

"The patient did not seem to have any obvious physical reasons to be unresponsive," the officer also noted. 

TMZ reports DEA joins investigation 

On Wednesday, TMZ reported that the Drug Enforcement Administration had joined the multi-agency investigation, according to TMZ's sources with direct knowledge of the probe. 

FOX Local reached out to the agency for comment, and a spokesperson said, "The DEA does not confirm or comment on active investigations."