Bennington was found dead Thursday.
Winter says a half-empty bottle of alcohol was found in the room, but no drugs were evident. Bennington struggled with drug and alcohol addictions at various times during his life.
A suicide note was not found.
An autopsy has not yet been scheduled.
Bennington was one of two lead vocalists for Linkin Park, who became one of the most commercially successful acts of the 2000s. They won countless awards, including Grammys, and their hits include "In the End," ''What I've Done" and "Numb."