(CNN) President Donald Trump said he would not have allowed the CIA to recruit the half-brother of North Korean leader Kim Jong Un "under my auspice."

Trump wouldn't confirm or deny reports that Kim Jong Nam had been working with the CIA prior to being killed in Malaysia in February 2017, saying that he didn't know anything about it.

"I know this: that the relationship is such that that wouldn't happen under my auspices, but I don't know about that. Nobody knows," he said.

The one-time heir apparent had become the black sheep of the Kim family before he was killed, after two women smeared nerve agent on his face in Kuala Lumpur International Airport in February 2017. Lawyers for both women, one Indonesian and the other Vietnamese, argued that their clients hadn't known what they were doing, believing they were taking part in a prank reality TV show.

In an article Monday, the Wall Street Journal claimed that the elder Kim brother had been a source for the CIA and had met with agency operatives several times.

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