As everyone knows I don't believe there is any video.
I think what is happening is basic police work.
They got the tip on CB, which fits with one of the main theories of the case - the burglar theory.
The more they looked at him, the more they have found circumstantial evidence. Accomplices who confirm he is a burglar, modus operandi. potentially stolen SIM card from OC. Inside help.
Then the rape case gave them a similar breaking/entering - plus the violence.
CB put himself in the frame with his careless talk and writings.
I do wonder though, without the body what specifically can link him to murder?