The Diddy trial could begin and end with jury deliberation, because the composition of the jury could determine whether Diddy spends the rest of his life in prison or goes free.

TMZ breaks down the factors in selecting a jury of Diddy's peers in our new documentary, "The Downfall of Diddy: His Defense," available now on Tubi.

Dr. Phil, a former jury consultant who masterminded Oprah's big win in the Texas beef trial, says it's critical to find open-minded jurors, and it's not as simple as asking if they're open-minded. One way to root that out ... asking prospective jurors if they've ever held a strong position and then changed their minds.

Jo-Ellan Dimitrius, the jury consultant for the defense in the O.J. Simpson murder trial, talks about the need to find jurors who are comfortable talking about lurid sex.

There's also strategy in finding a diverse jury, and whether to favor men or women, Black or white jurors, etc.

We assembled a mock jury for our documentary, which deliberated and argued fiercely ... then voted on whether Diddy was guilty or not.