So that means one or more jurors agreed with Billy that he was just in the wrong place at the wrong time.
In other words - an OJ jury.
He has been charged with 18 murders, but so far linked to a total of 24. Apparently, they are trying him one murder at a time. Even if he is acquitted in one trial, they can keep trying him on the other murders.
Eventually, they will get at least one capital murder conviction and the prosecutors can then introduce evidence of all of the other murders in the punishment phase.