A final cause of Bennington's death won't be confirmed until after the autopsy is completed, according to Ed Winter, a spokesman for the coroner's office.
The singer's body was discovered sometime Thursday morning. He was 41 years old.
His bandmate, Mike Shinoda, tweeted that he was "shocked and heartbroken" by the news of Bennington's death.
Bennington had been with the band for almost two decades. The act became a rock sensation in the late 1990s and early 2000s with best-selling albums like "Hybrid Theory" and "Meteora."
The band would release seven studio albums in all. Their latest album, "One More Light," was released earlier this year.
Bennington had always been open and honest about his past struggles with drugs and alcohol, especially around the time of his divorce from his first wife in 2005.
"I have been able to tap into all the negative things that can happen to me throughout my life by numbing myself to the pain, so to speak, and kind of being able to vent it through my music," he told Noisecreep in 2009. "‘Crawling,’ for example, by Linkin Park, is probably the most literal song lyrically I’d ever written for Linkin Park and that’s about feeling like I had no control over myself in terms of drugs and alcohol."
The singer said in interviews that he eventually got counseling and help in 2006 and stopped drinking.
In an open letter posted to Variety, he wrote of Cornell: "I’m still weeping, with sadness, as well as gratitude for having shared some very special moments with you and your beautiful family. You have inspired me in many ways you could never have known."
Today would have been Cornell's 53rd birthday.
Bennington is survived by his wife, Talinda Ann Bentley, and his six children.
ABC News' Julie Sone contributed to this report.