Siti Aisyah, a 25-year-old Indonesian native, killed Kim Jong Nam at the Kuala Lumpur airport in Malaysia on February 13 by spraying him in the face with the VX nerve agent - one of the most powerful poisons in the world.
"And if he fails to turn up given this notice, then we will go to the next step by getting a warrant of arrest from the court", he said.
"She said she was given a kind of oil, like baby oil", Indonesian deputy ambassador Andreano Erwin told reporters after meeting Aishah.
Malaysian officials said they had the proof after finding VX residue on the face and in the eyes of Kim Jong Nam.
Also Saturday, police confirmed that a raid earlier in the week on a condominium on the outskirts of Kuala Lumpur was part of the investigation.
Media reports also claim that Kim Jong Un ordered the assassination of his estranged half-brother. Malaysia Airports said it welcomed police efforts to further ensure safety.
However, Inspector General Khalid Abu Bakar refuted last week the two women's statements, and said they knew they were dealing with a toxic chemical and were aware of the assassination plot.
However, Erwin said Siti was physically healthy while Vietnamese officials said Huong was "in stable health". They are searching for four other male North Korean suspects who have fled the country and are believed to be back in Pyongyang.
Vietnamese Doan Thi Huong, who was one of the attackers.
Indonesian police chief Tito Karnavian said that the suspect, Siti Aishah, told police she had sprayed others in a similar manner three or four times, although only the Kim incident allegedly involved a risky substance.
They said that Malaysia was in violation of worldwide norms by not returning it but Malaysian officials want next of kin to come identify the body and provide a DNA sample before they were willing to hand it over.
Pyongyang is calling for the immediate release of the pair, describing them as "innocent women".
A North Korean resident of Kuala Lumpur has also been arrested. Siti Aisyah, the Indonesian, said she was paid $90 (85 euros), embassy officials said.
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Malaysia hasn't officially accused the North Korean government of carrying out the attack, but the attack has already strained relations. The diplomat is not known to have met the police yet.
Organophosphates are used in insecticides, medication and nerve agents, with those poisoned showing symptoms like increased saliva and tear production, diarrhea, vomiting, small pupils, sweating, muscle tremors and confusion.
The well-travelled and multilingual oldest son of late North Korean leader Kim Jong-il, he was once considered a potential future leader.