It's the latest example of the president siding with foreign adversaries over his own intelligence agencies.
Siti Aisyah and a co-defendant were accused of smearing VX nerve agent on Kim Jong Nam’s face in 2017.
A group that said it helped rescue the 21-year-old and his family posted the video online.
"To me, Kim is just a normal guy," he told an alternative diplomacy panel at the military academy.
Authorities fears others involved in the killing could want them silenced.
“It did it so fast and all over the body, so it affected the heart, it affected the lungs, it affected everything," Malaysia’s health minister said.
Eight North Koreans are wanted in connection with the case, including the diplomat.
VX nerve agent is chemical weapon classified as a weapon of mass destruction by the United Nations.