KUALA LUMPUR, Malaysia—Security footage has emerged of the killing of Kim Jong Nam last week, showing two attackers took less than three seconds to carry out the assault on the half-brother of North Korean dictator Kim Jong Un.

The video clips from security cameras were obtained by a Japanese media outlet and posted by a third party on YouTube. The video has since been removed from YouTube.

The footage from Kuala Lumpur International Airport showed Mr. Kim arriving alone at a busy, well-lit departures hall shortly before 9 a.m. on Feb. 13. Police said he had been in Malaysia about a week, and intended to take a 10:50 a.m. AirAsia flight back to his home in Macau.

From an airport mall area, Mr. Kim, wearing loafers, light-blue jeans, a sport coat and a flat cap, and with a black backpack slung over his right shoulder, strides past three police officers into a crowded departures hall. He pauses a moment to look up at a giant departures board, then walks a further 20 yards to AirAsia’s self-check-in kiosks.

In the next clip, Mr. Kim is standing at one of the kiosks when a person police believe was Siti Aisyah, a 25-year-old Indonesian woman who authorities said was working as a masseuse at a spa in Kuala Lumpur, approaches on his left, getting his attention.

Read the whole story from The Wall Street Journal.