Matthew Perry's autopsy was inconclusive — it could take 6 months for an official cause of death

• It could take months to determine the official cause of death of Matthew Perry. 
• The "Friends" star was found unresponsive on Saturday and has undergone an autopsy. 
• His cause of death is "deferred" until toxicology results come in, which can take 4-6 months.

The cause of Matthew Perry's death is unclear and could take months to be determined, according to publicly-available records.

The Los Angeles County Medical Examiner's Office listed the actor's primary cause of death as "deferred."

The site's guidelines state: "In cases where the cause of death cannot be determined at the time of autopsy, a deferred certificate will be issued until additional studies have been completed."

Los Angeles Police Capt. Scot Williams told the LA Times that they do not suspect foul play, but that the "cause of death may not be known for some time."

TMZ, which broke the news of the "Friends" star's death, published audio it says is from the police dispatch, which refers to a "drowning."

Authorities found Perry unresponsive in his hot tub on Saturday, the LA Times reported. He was 54.

Anonymous sources told the paper that no drugs were found at the scene. The sources said there were prescription medications present, making a toxicology report necessary.

The medical examiner's office told CNN that an autopsy had been performed. The toxicology report would indicate whether or not any foreign substances contributed to the cause of death. That can take "between four to six months," according to the medical examiner.

The medical examiner's records indicated that his body was ready to be released to his next of kin.

Perry, who played Chandler Bing, wrote candidly about his addiction issues in his memoir "Friends, Lovers and the Big Terrible Thing," describing years of alcohol and opioid abuse. He was an outspoken advocate for rehabilitation services and the reform of drug courts.

Celebrities and former costars posted emotional tributes following the news of his death. The official "Friends" X account said "we are devastated" and that "He was a true gift to us all."

An unnamed source told Page Six that the show's cast was "reeling" and plan to release a joint statement.