TOKYO (REUTERS) - Former North Korean spy Kim Hyon Hui said the alleged assassins of the estranged half-brother of North Korean leader Kim Jong Un appeared to be amateurs, the Mainichi newspaper reported on Saturday (Feb 18).

Kim Jong Nam, the older half-brother of Kim Jong Un, was killed in an apparent assassination on Monday at Kuala Lumpur international airport in the Malaysian capital.

Malaysian police said on Saturday that they had arrested a North Korean man in connection with the murder, after detaining two female suspects earlier this week.

Kim Hyon Hui, who bombed a Korean Air jet in 1987 after being trained as a North Korean agent, told the Japanese newspaper in a written interview that it was unthinkable that the women received strict training.

"I felt suspicious. They don't seem to have taken strict psychological and physical education and training in North Korea," Kim Hyon Hui told the paper.

According to Malaysian media reports, the women told police they had been involved in a prank. "They would not have run away if that was the case," Kim Hyon Hui said.

She also emphasised a link with North Korea as the date of the murder was close to the Feb 16 birthday of the late leader Kim Jong Il, father of Kim Jong Un and Kim Jong Nam, and that Kim Jong Il's nephew Lee Han Young was shot dead on Feb 15, 1997.

Lee Han Young, a North Korean defector, was shot and killed in South Korea by two assailants who were never caught but were suspected to be North Korean agents.

Kim Hyon Hui and another North Korean spy planted a bomb on a Korean Air flight in 1987, the year before South Korea was to host the Olympics. All 115 crew and passengers were killed when the plane exploded in mid-air over the Bay of Bengal.

Kim Hyon Hui was sentenced to death by a Seoul court but received a presidential pardon in 1990. She won sympathy as someone whom the reclusive North had used as a pawn, but largely dropped out of the public eye after leaving prison.