The only North Korean held in Malaysia in connection with the death of Kim Jong-nam has been released by police.
Officials have said there is insufficient evidence to charge Ri Jong Chol, and that he will be deported over immigration offences.
Nearly three weeks after the killing, Malaysia has condemned the use of the powerful VX nerve agent in the attack.
The Malaysia Foreign Ministry statement said it was “greatly concerned” its use could have endangered the public.
Mr Kim, the estranged half-brother of North Korean leader Kim Jong-un, died on 13 February at an airport in the Malaysian capital, Kuala Lumpur.
Two women were charged on Thursday with killing Mr Kim by smearing his face with VX nerve agent, a banned chemical weapon.
Doan Thi Huong from Vietnam and Siti Aisyah from Indonesia have said they thought they were taking part in a TV prank. They have yet to make a formal plea in their case.
Malaysia is seeking seven other North Korean suspects, including an embassy official.
It has has not directly blamed North Korea for the attack, but there is widespread suspicion Pyongyang was responsible.
North Korea has strongly rejected the allegations. It also rejected the findings of the post-mortem examination, having objected to it being carried out at all, and has demanded the body be handed over to them.
It has not yet confirmed that the body is that of Kim Jong-nam, acknowledging him only as a North Korean citizen. Mr Kim was travelling using a passport under a different name.
Ri Jong Chol had lived in Malaysia for three years but officials said he would be deported because he does not have valid travel documents. Reuters news agency reported that his work permit expired on 6 February 2017.
On Thursday, Malaysia announced it was cancelling visa-free travel for visiting North Koreans, citing security reasons.