Ri Jong Chol, the only North Korean so far detained over the death of the half-brother of North Korean leader Kim Jong-un, claims he is innocent after being released due to insufficient evidence.
Ri says the arrest and accusations were nothing more than a conspiracy against Pyongyang.
He addressed reporters outside the North Korean embassy in Beijing on Saturday, where he was staying after being freed and deported by the Malaysian authorities the day before.
The North Korean, in his first public appearance, accused the Malaysian authorities of trying to force him to confess, denouncing the proceedings as a plot to discredit the North Korean government.
Ri was detained on February 18, five days after Kim Jong Nam died after being allegedly attacked at Kuala Lumpur airport by two women, who, according to Malaysian and South Korean authorities, rubbed the deadly nerve agent VX on his face.
Ri, who is expected to return to his country on Tuesday and denies any wrongdoing, said he was in Malaysia involved in trading goods.
South Korea claims Pyongyang is behind the suspected murder of Kim Jong Nam, while North Korea says the death was caused by a heart attack.