https://www.amazon.com/Sealed-Envelope-J-Simpson-Murders/dp/B0BNL2JQGTThis is one of the best non-fiction books I've ever read.
tl;dr:
* Who: Nicole's family (parents, three sisters, half-brother)
* Who: Former LAPD cop named Ron Shipp, a shady bartender-to-the-stars named Ron Hardy, and a failed actor named Brian Kaelin. Each man was acquainted with Nicole & OJ, rejected romantically by Nicole, and Nicole's feelings for them ranged from dislike to hate.
* Why: The family was nearly 100% dependent on both O.J. and Nicole financially, and the divorce spelled disaster.
* Why: A variety of motives including revenge & monetary gain.
* How: Ron Shipp orchestrated the plot. Ron Hardy's apartment was 2 blocks away from Nicole's and was used as a base of operations. Kaelin drugged O.J. during the McDonald's trip, drew his blood, stole hair & fiber samples from his house.
* How: The "lost eyeglasses" story that was the catalyst for Ron Goldman's arrival at Nicole's was entirely staged by the murderers
* How: Shipp and Nicole's half-brother were the "knife-men", although at least five of the nine conspirators were seen in various locations near Nicole's condo by eyewitnesses from 9 to 11 pm
Keep in mind all of these claims are backed by extensively scrutinized evidence. There's no "making shit up", unlike many other books about the O.J. case.