Kim Jong-nam, the half-brother of North Korea's leader, was working for the CIA when he was murdered at the airport in Kuala Lumpur in 2017, according to a new book.

President Trump did not confirm or deny reports, only saying he wouldn't have allowed it.

Anna Fifield is the author of The Great Successor, an intimate look at Kim Jong-un's life and rise to power. She spoke to the BBC World News America's Jane O'Brien.