BANGKOK — A Vietnamese woman who was the only person convicted in the bold assassination of Kim Jong-un’s elder half brother, Kim Jong-nam, was released on Friday after serving 27 months in a Malaysian prison.

The release of Doan Thi Huong, 30, brings an end to the legal case in the murder of Mr. Kim, who died in February 2017 after two women smeared VX nerve agent on his face at Kuala Lumpur International Airport. The use of a severely toxic military weapon in such a public assassination was highly unusual.

An Indonesian woman arrested in the case, Siti Aisyah, 27, was released in March after high-level appeals by the Indonesian government to free her.

The police have identified at least seven North Koreans suspected of involvement in the killing, but none of them were ever brought to trial. Four escaped Malaysia immediately after the attack, and three others were allowed to leave after Pyongyang blocked Malaysian diplomats from leaving North Korea.