Mapped out yes, but it's a theory only of course until such time as new evidence or leads emerge. It might seem bizarre, but the circumstantial case against Mitchell is so flawed in every way including the totally inexplicable absence of his DNA at the scene AND in his house that there's actually nothing that can be described as a fact that links him to the murder. Even the so called link to Manson and the "Black Dahlia" was disproved. Nothing was ever found in his house or on his devices to suggest he had ever liked Manson or even heard of the" Black Dahlia". I definitely believe the wrong person is in jail.
Discussing possible motives would make it too easy to work out who the person (or persons) is that I think may have killed J. I don't have proof, nobody does.....yet, so in case I am wrong I have to refrain from naming them or by implication.
I suspect as a Goth LM did enjoy listening to Marilyn Manson music. Given the number of views on youtube he seems rather popular: 186,076,769
https://www.youtube.com/watch?v=QUvVdTlA23wI've included a couple of tracks on my playlist as he does covers for some of my fave 80's tracks

How on earth can anyone be condemned for enjoying listening to the music of a popular musician with global appeal?
Scottish schoolgirl, Nicola Ann Raphael, committed suicide after enduring years of bullying because she dressed in a goth style. According to the following, shortly after her death she had been due to attend a Marilyn Mason concert and MM was seen at the concert comforting her mother.
I know Scots are intolerant over allegiances to football clubs: Celtic v Rangers but hadn't appreciated it extends to choice of music too.
https://en.wikipedia.org/wiki/Suicide_of_Nicola_Ann_Raphael