The 30-year-old's body was discovered on Feb. 22 inside the Dallas home he shared with his girlfriend.
According to the Dallas County Medical Examiner, his initial cause of death remains undetermined pending the toxicology report.
As Radar previously reported, Gable had a history with drug abuse before he passed away. His longtime ex-girlfriend, Heather Chadwell, told Radar that while she was with him he "would disappear for days on end."
"We were battling our own addiction issues and it was too much," said Chadwell.
Before Gable's tragic death, he had been working on a documentary honoring his iconic grandfather.
"Hollywood has told Elvis Presley's story, Johnny Cash's story, and the magical behind-the-scenes stories of many different iconic artists. But my Grandfather was the biggest: He was The King. I'm happy his story will finally be told," Gable wrote in his proposal for the project.
He is survived by his girlfriend, Summer, and their 2-year-old daughter, Shore LaRea Gable.
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