Three North Koreans being questioned over the murder of Kim Jong Nam have been returned home in a “swap” deal by the Malaysian government for political prisoners of its own.
Malaysian police took statements from the three men before they were allowed to leave the country, as the hunt continues for the killers.
US officials say the assassination was carried out by North Korean agents.
“We have obtained whatever we want from them... They have assisted us and they have been allowed to leave,” Malaysian police chief Khalid Abu Bakar said on Friday.
There were no grounds to hold the men any longer, Reuters reported Bakar saying.
My investigation... has not been compromised." Khalid Abu Bakar
Malaysian prosecutors have so far charged two women - an Indonesian and a Vietnamese - with killing Jong Nam using VX nerve agent.
The chemical is so lethal that it is on a UN list of weapons of mass destruction.
Jong Nam is the half-brother of the nuclear-armed state’s dictator leader, Kim Jong-un.
He was killed in a busy terminal at Kuala Lumper International Airport in February.
North Korea had issued a travel ban after Malaysia held one of its citizens for questioning for a week.
It stranded three diplomats and their family members - including four children - in Pyongyang.
Which left Malaysia with little option but to accede to North Korea’s demands for the return of Jong Nam’s body and its three nationals wanted for questioning.
According to ‘Plane Tracker’, the flights carrying each nation’s citizens departed Pyongyang and Kuala Lumper at the same time.
A North Korean statement released on Thursday said both countries had managed to “resolve issues arising from the death of a DPRK national”.
Malaysian Prime Minister Najib Razac, who is currently on an official visit to India, said: “I had a deep personal concern about this matter, and we worked intensively behind the scenes to achieve this successful outcome.
“Many challenges were overcome to ensure the return of our fellow Malaysians.”
“The government believes strongly in the principles of justice and sovereignty. Our police investigation into this serious crime on Malaysian soil will continue.
He added: “I have instructed for all possible measures to be taken to bring those responsible for this murder to justice.”
Malaysian police have so far arrested three people in connection with the murder.
The first is 25-year-old Indonesian-national Siti Aishah.
The other held Vietnamese travel documents bearing the name Doan Thi Huong, 28, reports the Associated Press.
Still photos of the CCTV video, confirmed as authentic by police, showed her in a skirt and long-sleeved white T-shirt with “LOL” emblazoned across the front.