Malaysia said it would release and deport a North Korean man arrested in connection with the death of Kim Jong Un’s half-brother due to a lack of evidence, and announced it would scrap visa-free travel for citizens of the reclusive state.

Ri Jong Chol was arrested four days after Kim John Nam died after an apparent poisoning at the Kuala Lumpur airport on Feb. 13. Malaysian Attorney General Mohamad Apandi Ali said he will be deported because he does not have valid travel documents.

He will not be charged here as there is insufficient evidence against him, Apandi told Malaysia’s Star Online.

The Star Online reported that Ri, a chemistry expert, was suspected of having driven one of four North Korean men thought to have masterminded the assassination. The four are thought to have fled Malaysia and returned to Pyongyang, it said.

Ri, who will be deported on Friday, had a work permit that was valid until Feb. 6 this year, Reuters reported.

South Korea has accused North Korea of orchestrating the death on behalf of the North’s leader Kim Jong Un.

Thae Yong Ho, one of the highest-ranking defectors from the North, told Hong Kong-based Phoenix TV that Kim Jong Un must have approved of the assassination. Thae, the former deputy head of the North Korean Embassy in London, fled to South Korea last year.

Speaking from the South Korean capital Seoul, he said: “North Korea is a society ruled in terror. For a big decision like killing Kim Jong Nam, no one could make a decision like that except Kim Jong Un.”

Malaysia is one of the few places that North Koreans can travel to without a visa and Malaysians can also enter North Korea without visas.

Deputy Prime Minister Ahmad Zahid Hamidi said the arrangement would be scrapped for North Koreans from Monday for national security reasons, the Associated Press reported.

He criticized North Korea’s ambassador to Malaysia, who accused the country of “colluding with hostile forces.”

“We don’t want to make enemies, but if they had used Malaysia for their own agenda, they should not accuse Malaysia and tarnish our image on the international stage,” Zahid said, according to the AP. “We will act firmly to guarantee the safety of our people. Don’t ever use Malaysia as a base to do anything you like.”

Two women accused of attacking Kim Jong Nam with VX nerve agent were charged with murder Wednesday. If convicted, Indonesian Siti Aisyah, 25, and Doan Thi Huong, 28, of Vietnam, could face the death penalty.

Malaysian police said Siti and Doan placed the deadly nerve agent VX on Kim’s face at the airport. He died on the way to a hospital.

The women claim they thought they were taking part in a televised prank. Ri Tong Il, the former North Korean deputy ambassador to the United Nations, told reporters Thursday that Kim Jong Nam, who he referred to by his alias Kim Chol, took medication for heart disease, diabetes and high blood pressure and probably died of a heart attack.

Kim Jong Nam was the eldest son of North Korea’s late leader Kim Jong Il, but he fell out of favor with his father. He was on his way home to Macau, a Chinese gambling mecca, when he was killed.