A chronology of key events in the case:
Feb. 13, 2017: A North Korean man, waiting to board a flight to Macau at a low-cost airport terminal in Malaysia, complained to airport officials that someone grabbed him from behind him and smeared his face with some liquid. He was sent to the airport clinic and pronounced dead on the way to a hospital.
Feb. 14, 2017: International media broke the news that Kim Jong Nam was murdered in Malaysia. Police later said the victim was a North Korean man known as Kim Chol based on his passport.
Feb. 15, 2017: Doan Thi Huong of Vietnam was detained at the same airport terminal where Kim was killed.
Feb. 16, 2017: Indonesia's Siti Aisyah was detained. Malaysia's then-Home Minister Ahmad Zahid Hamidi confirmed that Kim Chol was Kim Jong Nam.
Feb. 18, 2017: Police arrested North Korean Ri Jong-chol, 47, who is believed to be a chemical expert.
Feb. 19, 2017: Police announced they were looking for seven North Korean suspects in connection with the murder. Police later said four of them were believed to have left the country and later sought Interpol's help to detain them.
Feb. 24, 2017: Officials said Kim was killed by the toxic VX nerve agent, listed by the U.N. as a weapon of mass destruction.
Feb. 26, 2017: Officials said they found no hazardous material nor any trace of VX after a sweep of the airport terminal where Kim was killed, and declared it safe.
Feb. 27, 2017: South Korean lawmakers said the country's National Intelligence Service had told them that four of the North Koreans identified as suspects by Malaysian authorities were spies from North Korea's Ministry of State Security. The lawmakers also said they were told that two other suspects were affiliated with North Korea's Foreign Ministry and that leader Kim Jong Un directed a "state-organized terror" to kill his half brother. The lawmakers didn't say how South Korea's spy agency got the information.
March 1, 2017: Aisyah and Huong were charged in a Magistrate's Court with Kim Jong Nam's murder and faced the death sentence if convicted.
March 2, 2017: Ri Tong Il, a former North Korean deputy ambassador to the United Nations who was leading a high-level delegation to Malaysia to seek Kim's body, said a heart attack likely killed the victim, not VX nerve agent as the autopsy showed.
March 3, 2017: North Korean Ri Jong-chol was released due to a lack of evidence and deported.
March 4, 2017: The Malaysian government expelled North Korean Ambassador Kang Chol, days after scrapping a visa-free entry for North Koreans. Kang Chol, who had denounced Malaysia's investigations into Kim's death and accused Kuala Lumpur of colluding with outside forces to defame Pyongyang, was given 48 hours to leave the country.
March 7, 2017: North Korea banned Malaysian citizens in its country from leaving as tension escalated over Kim's killing. Malaysia responded with a similar ban.
March 30, 2017: Nine Malaysians held in Pyongyang returned home after the two countries struck a deal to end a diplomatic row. Malaysia released Kim's body to Pyongyang and also allowed North Koreans to leave, including a North Korean Embassy official and an Air Koryo employee wanted by police for questioning over Kim's death.
Oct. 2, 2017: The joint trial of Aisyah and Huong began in the High Court. They pleaded not guilty. Their lawyers said they were pawns in a political assassination orchestrated by four North Korean suspects who fled Malaysia on the day of Kim's killing. The four men were accused in the charge sheet of conspiring with the women to kill Kim.
Aug. 18, 2018: A High Court judge ordered the two women to enter their defense after ruling there was enough evidence to infer that they had engaged in a "well-planned conspiracy" with the four missing North Korean suspects to kill Kim.
Nov. 7, 2018: The judge set Jan. 7 for the trial to resume after Aisyah's lawyers complained that some witnesses were unreachable.
Jan. 7, 2019: The trial was postponed to March. Aisyah's lawyers sought time to appeal to higher courts to obtain statements given by witnesses to police that they said are crucial for her case.
March 11, 2019: Prosecutors unexpectedly dropped the murder against Aisyah, without giving any reason. Aisyah was given a discharge not amounting to an acquittal by the court. She was flown back to Jakarta in a private jet on the same day. Indonesian officials said her release was due to Jakarta's continual high-level lobbying. A distraught Huong, who was supposed to start her defense, said she was in a shock. Her lawyers sought a postponement of the trial and asked prosecutors to also withdraw the murder charge against Huong.
March 12, 2019: Vietnamese Foreign Minister Pham Binh Minh phoned his Malaysian counterpart, Saifuddin Abdullah, requesting the court to be fair and also free Huong. Malaysian Prime Minister Mahathir Mohamad said Aisyah's release was based on the rule of law, amid allegations the government had interfered in the trial.
March 13, 2019: Law Minister Liew Vui Keong said Malaysia's attorney general has sole discretion in withdrawing the charge against Aisyah and that the government cannot interfere with the attorney general's power.
March 14, 2019: Prosecutors told the court that the attorney general ordered the murder case to proceed against Huong. They didn't explain why the attorney general refused to acquit her. Huong's lawyers accused the attorney general of being unfair and discriminating against her. The judge postponed hearing to April 1 after Huong told the judge she was unwell and stressed.
April 1, 2019: Prosecutors said the attorney general offered a reduced charge of "voluntarily causing injury with a dangerous weapon" to Huong following renewed pleas from the Vietnamese government and her lawyers. Huong pleaded guilty and the judge sentenced her to three years and four months in jail. Her lawyers said she will be freed early next month after a one-third remission for good behavior. Huong said she was "very happy" and that the sentence was fair.