"Kim Jong Nam likely had enough personal, intimate, and family information in his head to warrant an approach from CIA - or any intelligence agency - for debriefing purposes", said Darrell M. Blocker, a longtime CIA operative and now an ABC News contributor.
"I just received a attractive letter from Kim Jong Un".
Kim was killed at the Kuala Lumpur International Airport in Malaysia on February 13, 2017, following his meeting with the alleged Central Intelligence Agency agent. I would tell him that would not happen under my auspices.
Washington is seeking to rebuild momentum in stalled talks with Pyongyang, aimed at getting North Korea to dismantle its nuclear weapons program.
On the same February 2017 journey during which he was killed at Kuala Lumpur International Airport, Fifield notes, a hotel elevator security camera pictured him with "an Asian-looking man who was reported to be an American intelligence agent".
"There was a nexus" between the USA spy agency and Kim Jong-nam, the source said on Monday.
United States officials have said that they are certain that Mr Kim, who had been based in Macau, had been communicating with security services of other nations, with China in particular.
Kim lived primarily outside North Korea, usually residing just outside of China in Macau. The CIA declined to comment.
Lawyers for the women have said that they were pawns in a political assassination with clear links to the North Korean Embassy in Kuala Lumpur and that the prosecution failed to show the women had any intention to kill. The murder was part of an extended purge carried out by Kim Jong-un against potential rivals and their supporters, as he consolidated his power.
Murder charges were dropped against the women earlier this year.
Former officials said that he had nearly certainly been in contact with security services from other countries, particularly China's, although he had no known power base in Pyongyang and had not lived in the country for several years.
News of the CIA's relationship with Kim Jong-nam comes as nuclear diplomacy between the US and North Korea is at a standstill following a February summit in Hanoi between Mr. Kim Jong-un and US President Donald Trump that ended without an agreement.