The "L.A. Times" says Matthew was discovered UNDER WATER in his hot tub by a "bystander", who then called 911.
By the time help arrived, the bystander had repositioned Matthew with his head out of the water. But he was already dead.
An autopsy has been completed, but an official cause of death is pending the results of toxicology and other tests.
Here are some other developments:
1. In the months leading up to his death, Matthew was in the process of starting a foundation to help people suffering from substance abuse.
2. Matthew's memoir, "Friends, Lovers and the Big Terrible Thing", hit #1 on Amazon following his death.
3. TBS is doing a Best of Chandler "Friends" marathon starting Wednesday and running through Sunday.
4. Matthew's "Fools Rush In" co-star Salma Hayek posted some pics, and said, quote, "I will continue to cherish your silliness, your perseverance, and your lovely heart. Farewell, sweet Matthew, we will never forget you."