Saudi Arabia's crown prince said he bears responsibility for the killing of journalist Jamal Khashoggi last year by Saudi operatives "because it happened under my watch," according to a PBS documentary to be broadcast next week. Mohammed bin Salman, the kingdom's de facto ruler, has not spoken publicly about the killing inside the Saudi consulate in Istanbul. The CIA and some Western governments have said he ordered it, but Saudi officials say he had no role. The death sparked a global uproar, tarnishing the crown prince's image and imperilling ambitious plans to diversify the economy of the world's top oil exporter and open up cloistered Saudi society. He has not since visited the United States or Europe. "It happened under my watch. I get all the responsibility, because it happened under my watch," he told PBS' Martin Smith, according to a preview of a documentary, "The Crown Prince of Saudi Arabia," set to air on Oct. 1, ahead of the...