The cause of Matthew Perry's death is unknown and has been "deferred" pending further investigation.
The LA Times and TMZ, which first reported the Friends actor had died, said the star was found unresponsive in a hot tub at his house on Saturday.
Perry's post-mortem examination was inconclusive, while officials await the results of toxicology tests.
There were no obvious signs of trauma, an LA Police spokesperson confirmed to CBS News, the BBC's US partner.
The LA County Medical Examiner's office updated their file on Sunday to say the case had been deferred.
This usually means that the post-mortem is complete but more detail is needed.
A Los Angeles Fire Department spokesperson told the BBC on Sunday that first responders went to an address in the Pacific Palisades area, regarding a "water emergency" of an unknown type, but did not name Perry.
The Friends star, who died at the age of 54, was best known for playing wisecracking Chandler Bing in the hugely popular '90s TV sitcom.
The show, which followed the fortunes of six young friends living in New York City, aired from 1994 until 2004.
Its final episode was watched by 52.5 million in the US, making it the most watched TV episode of the 2000s.
But while at the height of his fame, Perry was battling with addiction to painkillers and alcohol, and attended rehabilitation clinics on multiple occasions.
In 2016, he told BBC Radio 2 that he could not remember three years of filming during Friends, because of drink and drugs.