Melnikaitė was born to a family of a Russian mother Antonina Illarionovna and a Lithuanian father Juozas Melnikas in Zarasai.

Melnikaitė completed a primary school in Rokiškis and started working at Avanti confectionery at age 14 and studied sewing.

[2] After the German invasion of the Soviet Union, Melnikaitė along with other Komsomol members was evacuated to Russia where she took a job at a machine tool plant in Tyumen.

[3] Melnikaitė and a few others were assigned to the native Zarasai where she joined the Soviet partisan group Kęstutis under the name of Ona Kuosaitė.

For example, in March 1944, Antanas Sniečkus wrote in Tiesa that the shootout lasted a day and that Melnikaitė personally killed seven policemen, was badly injured, attempted to commit suicide with a grenade, and even after brutal torture did not betray her fellow partisans.

[3] Until 1965, when documents were discovered that proved she was shot, her biographers claimed that she was publicly hanged and that her last words praised the Lithuanian SSR and comrade Stalin.