He was released on October 28, 2013.He didnt have gallons, probably 10cc of that stuff would kill an elephant. I think his Dr. wanted him dead and purposely ODed him. Hes in prison for murder I believe.
There are some facts and a timeline on the events here:
https://www.cnn.com/2013/04/03/us/conrad-murray-fast-facts/index.html