In November O. J. Simpson sat for what would have been one of the most unusual interviews in television history —- a hypothetical recounting of how, if he had been the killer, he might have murdered his ex-wife, Nicole Brown Simpson, and her friend Ronald L. Goldman more than a decade ago.

The interview, taped in Miami to publicize a book, “If I Did It,” was never broadcast, as public outrage exploded over the idea that Mr. Simpson might profit from the murders that many people believe he committed, despite his acquittal in a criminal trial.

But a partial transcript of the interview Mr. Simpson had with Judith Regan, the publisher of the proposed book, makes vividly clear the disquieting nature of the entire exercise...