Doan Thi Huong, the second of two women accused of murdering North Korean dictator Kim Jong-un’s half-brother, Kim Jong-nam, in 2017, was released from prison in Malaysia on Friday. Her co-defendant, Siti Aisyah, was abruptly released in March, with all charges dropped.

Huong and Aisyah were accused of killing Kim Jong-nam at the Kuala Lumpur airport by smearing a chemical weapon on his face. The women said they were innocent dupes tricked into carrying out the assassination by North Korean agents who fooled them into thinking it was a harmless prank for a TV show.

The Associated Press noted on Friday that because Malaysia never formally accused North Korea of orchestrating the murder, Huong’s release effectively closes the case, turning Kim Jong-nam’s murder in broad daylight at a crowded airport with a banned chemical weapon into an unsolved mystery. The four enigmatic North Korean agents thought to have staged the murder fled Malaysia immediately afterward and have never been found, despite a “red notice” international warrant from Interpol.

“The planners, organizers, and overseers of the assassination of Kim Jong Nam have indeed ‘gotten away with it.’ No one will be held responsible for this horrific attack in which a weapon of mass destruction was used to kill a human being in an international airport,” former Acting U.S. Assistant Secretary of State Evans Revere told CNN.

CNN noted that Malaysian prosecutors were originally very insistent that Huong and Aisyah knew they were participating in an assassination, leading observers to suspect the case was highly politicized by the Malaysian and Indonesian governments, both of which undertook elections while the trial was in progress.

CNN’s analysts credited North Korea and its allies with using diplomatic pressure to squelch the murder investigation as nuclear diplomacy heated up in 2018 and noted that North Korea’s neighbors are accustomed to writing off far worse outbursts of psychotic violence from the dictatorship, so a plot that killed one man and landed two women in prison is relatively sedate by Pyongyang’s standards.

The charge of murder was dropped against Huong after police released Aisyah and she accepted a plea deal for lesser charges, so she was serving a 40-month sentence for “causing injury” and was set free on Friday with credit for time served and good behavior.

“I met Doan yesterday at the prison to give her new clothes and a pair of shoes. She was obviously very happy to be released and looks forward to being reunited with her family,” her lawyer, Hisyam Teh Poh Teik, told the BBC on Friday. Huong reportedly hopes to pursue a singing and acting career after she returns to Vietnam.