The mob theory includes the approval of Sam Giancana in Chicago.
Supposedly Sam was upset that the Kennedys were going after the mob including Marcello whom they grabbed off the street and dumped in Guatemala after they lost a hearing to deport him.
Giancana sent Roselli and another guy to talk to Joe Kennedy to ask him the remind the boys that the mobbed had helped carry WV in the election (union pressure).
Kennedy said he would talk to them when the family authored for Christmas. before Christmas Joe had a massive stroke.
Killing JFK would have violated a mob code since 1891 to kill cops and politicians.
Showtime ran a biopic of Joe Bonanno. He retired in Arizona and IIRC he died of old age. His retirement was approved by the commission.
After the flick, they had an interview with the old man. He said that Chicago had JFK killed and one of the shooters was in the sewer grate.
I have seen items in which the sewer grate was dismissed as a possible shooter site. I was in Dealey plaza a couple of years ago. Don’t know how anyone could get a good angle from the sewer openings on the curb.
Any theory with Chicago in it does not exclude Marcello. I believe he was under the auspicious of Giancano.